Initial commit
Bump to Crosswalk 6 beta and build Android stuff
Use pre-compiled Crosswalk for Android

For building this package from the source, we basically build Crosswalk
3 times: desktop, Android ARM and Android x86. This takes an enormous
amount of time on the PPA bots.

I might consider split this package into 3 so we can ship the source
package with sources only as usual.
Build for trusty and do not make warnings fatal

As it stops at:
'const gchar* const* g_settings_list_schemas()' is deprecated