Support registration & login with phone number (#742)

* WIP msisdn sign in

* A mostly working country picker

* Fix bug where you'dbe logged out after registering

Stop the guest sync, otherwise it gets 401ed for using a guest
access token for a non-guest, causing us to beliebe we've been
logged out.

* Use InteractiveAuth component for registration

* Fix tests

* Remove old signup code

* Signup -> Login

Now that Signup contains no code whatsoever related to signing up,
rename it to Login. Get rid of the Signup class.

* Stray newline

* Fix more merge failing

* Get phone country & number to the right place

* More-or-less working msisdn auth component

* Send the bind_msisdn param on registration

* Refinements to country dropdown

Rendering the whole lot when the component was rendered just makes
the page load really slow, so just show 2 at a time and rely on
type-to-search.

Make type-to-search always display an exact iso2 match first

* Propagate initial inputs to the phone input

* Support msisdn login

* semicolon

* Fix PropTypes

* Oops, use the 1qst element of the array

Not the array of object keys which has no particular order

* Make dropdown/countrydropdown controlled

* Unused line

* Add note on DOM layout

* onOptionChange is required

* More docs

* Add missing propTypes

* Don't resume promise on error

* Use React.Children to manipulate children

* Make catch less weird

* Fix null dereference

Assuming [0] of an empty list == undefined doesn't work if you're
then taking a property of it.

src/components/views/login/CountryDropdown.js

@@ -0,0 +1,123 @@
+/*
+Copyright 2017 Vector Creations Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+
+import sdk from '../../../index';
+
+import { COUNTRIES } from '../../../phonenumber';
+import { charactersToImageNode } from '../../../HtmlUtils';
+
+const COUNTRIES_BY_ISO2 = new Object(null);
+for (const c of COUNTRIES) {
+    COUNTRIES_BY_ISO2[c.iso2] = c;
+}
+
+function countryMatchesSearchQuery(query, country) {
+    if (country.name.toUpperCase().indexOf(query.toUpperCase()) == 0) return true;
+    if (country.iso2 == query.toUpperCase()) return true;
+    if (country.prefix == query) return true;
+    return false;
+}
+
+const MAX_DISPLAYED_ROWS = 2;
+
+export default class CountryDropdown extends React.Component {
+    constructor(props) {
+        super(props);
+        this._onSearchChange = this._onSearchChange.bind(this);
+
+        this.state = {
+            searchQuery: '',
+        }
+
+        if (!props.value) {
+            // If no value is given, we start with the first
+            // country selected, but our parent component
+            // doesn't know this, therefore we do this.
+            this.props.onOptionChange(COUNTRIES[0].iso2);
+        }
+    }
+
+    _onSearchChange(search) {
+        this.setState({
+            searchQuery: search,
+        });
+    }
+
+    _flagImgForIso2(iso2) {
+        // Unicode Regional Indicator Symbol letter 'A'
+        const RIS_A = 0x1F1E6;
+        const ASCII_A = 65;
+        return charactersToImageNode(iso2,
+            RIS_A + (iso2.charCodeAt(0) - ASCII_A),
+            RIS_A + (iso2.charCodeAt(1) - ASCII_A),
+        );
+    }
+
+    render() {
+        const Dropdown = sdk.getComponent('elements.Dropdown');
+
+        let displayedCountries;
+        if (this.state.searchQuery) {
+            displayedCountries = COUNTRIES.filter(
+                countryMatchesSearchQuery.bind(this, this.state.searchQuery),
+            );
+            if (
+                this.state.searchQuery.length == 2 &&
+                COUNTRIES_BY_ISO2[this.state.searchQuery.toUpperCase()]
+            ) {
+                // exact ISO2 country name match: make the first result the matches ISO2
+                const matched = COUNTRIES_BY_ISO2[this.state.searchQuery.toUpperCase()];
+                displayedCountries = displayedCountries.filter((c) => {
+                    return c.iso2 != matched.iso2;
+                });
+                displayedCountries.unshift(matched);
+            }
+        } else {
+            displayedCountries = COUNTRIES;
+        }
+
+        if (displayedCountries.length > MAX_DISPLAYED_ROWS) {
+            displayedCountries = displayedCountries.slice(0, MAX_DISPLAYED_ROWS);
+        }
+
+        const options = displayedCountries.map((country) => {
+            return <div key={country.iso2}>
+                {this._flagImgForIso2(country.iso2)}
+                {country.name}
+            </div>;
+        });
+
+        // default value here too, otherwise we need to handle null / undefined
+        // values between mounting and the initial value propgating
+        const value = this.props.value || COUNTRIES[0].iso2;
+
+        return <Dropdown className={this.props.className}
+            onOptionChange={this.props.onOptionChange} onSearchChange={this._onSearchChange}
+            menuWidth={298} getShortOption={this._flagImgForIso2}
+            value={value}
+        >
+            {options}
+        </Dropdown>
+    }
+}
+
+CountryDropdown.propTypes = {
+    className: React.PropTypes.string,
+    onOptionChange: React.PropTypes.func.isRequired,
+    value: React.PropTypes.string,
+};