Network page interface

[aprokopenko]

1. Update network page interface to be in a corporate style (wp widgets like UI. the same as just custom fields admin page).
2. replace jquery autocomplete with select2.js
3. rename "Icon" to "Language Alias"
4. if nothing found in the table > show such message:
   "No settings were added here. Be the first who add a new language to this blog"
   And the button in the center of the next row

[aprokopenko]

feedback Feb 10:

1. line up all (button still has wrong pos)
2. adjust width. content should be on full screen width. in the table first column should take max possible width. all other min possible width
3. Rename menu item to "Site Languages"
4. Add new paragraph, saying that user can control which post types can be translated on the settings page. (settings page should be a link to this settings page)