MDL-38923 theme_bootstrapbase: pre-integration fixups

* Fixed the way we added the block class to the dock panel in dock.js
* Added a class to the h2 that is used to test dock title width
* Fixed RTL alignment issues as best I could at present
* Fixed overlap of dock + navbar on small screens
* Fixed the docked block width to be constrained to the available space
* Fixed hidden actions on docked blocks