Fist pass at fixing the RTL issue using cssjanus

Added cssjanus to create rtl files.
Now we are creating:
_inc/jetpack-admin.css -> _inc/jetpack-admin-rtl.css
_inc/jetpack-banners.css -> _inc/jetpack-banners-rtl.css
_inc/jetpack-network.css -> _inc/jetpack-network-rtl.css
_inc/jetpack.css -> _inc/jetpack-rtl.css
Options: swapLtrRtlInUrl=false, swapLeftRightInUrl=false
and the minified
_inc/jetpack-admin.min.css -> _inc/jetpack-admin-rtl.min.css
_inc/jetpack-banners.min.css -> _inc/jetpack-banners-rtl.min.css
_inc/jetpack-network.min.css -> _inc/jetpack-network-rtl.min.css
_inc/jetpack.min.css -> _inc/jetpack-rtl.min.css
Fixes the issue #659, categories filtering for the main page when the page is translated
Updates to the RTL styling

Added the css.map files, minor tweak for rtl and icons.
Made sure that we includes the genericons.
Added rtl to the watch tasks

Now we get watch
Sass, autoprefix, rtl
Regenerated css, and map files
Merge the RTL UI changes

- Added RTL Support for the jetpack admin
- Use cssjanus to automate the rtl file creation.
- Regenerated css and map files
- Fixed the categories display filtering.