[embedding tutorial] Fix typo

You need the "webview" package, not "cordova", now.
Update coding style link in 'Contributing code' page
Variable is JAVA_HOME, not ANT_HOME

Fixes https://crosswalk-project.org/jira/browse/XWALK-2025
[Cordova] Add note about installing nodejs

Fixes https://crosswalk-project.org/jira/browse/XWALK-2026
[report bugs] Tweak formatting of submitted report

The report template had some markup which rendered poorly in
Jira. Modified to use bold font to mark the section headings.
[WebRTC] Add tutorial
[WebRTC] Add note about Crosswalk versions which support WebRTC
[WebRTC] Specify exact version where WebRTC works on x86

WebRTC on x86 only works on a late version 7, not all 7.* versions.
[WebRTC] Add WebRTC sample to crosswalk-samples