Add jQuery Mobile 1.4.0-alpha.1
Update to 1.4.0-beta.1
Update to 1.4.0-rc.1
Update to final 1.4.0 release
Remove "3.1" from description/summary of gem

This really works for any “recent” release of Rails (3.1, 3.2, 4.0,
etc.) so no need to specific 3.1 anymore.
Merge branch '1.4.0'

1.4.0 is officially released!