Objectives:
* Got rid of mw prefixing in tools, inspectors and dialogs
* Simplify tool classes so they can be generically used as items in bars, lists and menus
* Add support for a catch-all toolbar group
* Simplify tool registration, leaning on tool classes' static name property
* Move default commands to command registry
* Move default triggers to trigger registry
* Get language tool working in standalone
Change-Id: Ic97a636f9a193374728629931b6702bee1b3416a
This is the infrastructure for the Language Inspector prototype, defining
the dm and ce pieces of the <span lang='xx' dir='yy'> annotations. It also
sets up a visual indicator for language blocks (with informational tooltip
for the user while editing. The UI is built on top of this.
Bug: 47759
Change-Id: I239eef5124e29369ea9c5d8c0f49b2f6a61bc053
