Widget Visibility: update wording for the logged in condition

"Logged In" and Logged Out" sound better than "yes" and "no" imo
See #826
Merge pull request #1172 from jeherve/update/widget-visibility-loggedin-wording

Widget Visibility: update wording for the logged in condition
Open Graph: add AIOSEO back to the list of conflicting plugins
Merge pull request #1202 from jeherve/add/aioseo-og-tags-conflict

Open Graph: add AIOSEO back to the list of conflicting plugins
PHPDoc Tidying
Fn `Jetpack::is_development_version()`

Keys off the JETPACK__VERSION constant and flags if it’s a `-dev` or
`-beta` version or the like, or a straight-up number!
Change how we're adding the concatenated css.

Use core’s native RTL support.  Also, for stable releases, use the
Jetpack Version.  For development builds, use filemtime.
Do not use the imploded file if ( SCRIPT_DEBUG )
Fix is_development_version

It was testing the reverse!
Precompile module tags for translation dynamically

This ensures that any new tags added later will be included in the
translation set.
Regenerate POT file.
Bump version numbers to beta4.
Uniform Jetpack Endpoints.

+ Improve base class.
+ Add $expected_actions property
+ Remove unused functions
Add modules bulk activation/deactivation logic.
Ooops
Return the non ulrencoded version as id.
Plugin install endpoint: adding an endpoint to install a plugin
Add bulk install capacity.

Needs some testing, and tests :)
Add test case for plugin installation endpoint.
Moved dependencies out of the install function.