Create missing .dev stylesheets and fix RTL handling

[nacin]

We need to create any missing .dev stylesheets and also fix WP_Styles to handle dev versions of RTL sheets properly.

[matveb]

Added the missing rtl.dev.css files. Not sure if this is the right way to do it.

[nacin]

(In [13238]) Minify remaining RTL css files, and ie.css. See #12292.

[nacin]

Sorry matveb, didn't see your attachment. (Attachments are silent posts in our notification system.)

I've minified the remaining RTL sheets, which included some pretty tiny sheets, but it will allow us to use -rtl.dev.css files effectively and without too much hacking.

I've attached a patch that takes care of script-loader.php and WP_Styles. Comments welcome. We can probably make a few more changes and get rid of some of the smaller minified RTL files.

[nacin]

Full RTL+.dev support

[nacin]

(In [13239]) Suffix and version bump for ie.css, see #12292

[nacin]

I'd like to come up with a better way to do this (see 12292.2.diff​ as a start) that prevents us from minifying stylesheets we don't need to minify (take ​this one for example), leading to file bloat.

Patch welcome.

[automattor]

(In [13351]) Proper RTL + .dev.css support, first pass. See #12292

[nacin]

Closing as fixed for now. Ideally, we'd make some changes to the dependencies to prevent us from minifying RTL stylesheets we don't need to minify.