Implemented TiledButtonGroupManager. Improved ChannelSelector class.

* Removed ChannelSelectorRegion class and appropriate instances
  since now it's redundant.

* Now ChannelSelector class contains three instances
  of TiledButtonGroupManager class (AUDIO, RECORD, PARAM).
  This managers own appropriate buttons, position it, responsible
  for all animations, fuzzy selection via dragging mouse, etc.
* Button group managers minor fixes.

Recording disk writes dedicated thread

Fix CAR plugin loading on OS X, compiler warnings

Include definitions of LinearSmoothedValueAtomic's template methods in its header file (required because the explicit instantiations built in to the OE application are not visible to plugins on OS X)

* This class position buttons inside itself
  as tiles and has feature which gives
  us fuzzy button selection possibility via
  mouse drag (or SHIFT+mouse drag for deselection).

* LinearButtonGroupManager class now have the same functionality as
  ButtonGroupManager class had before.
* ButtonGroupManager now is the base class for all other button group
  managers.
* Appropriate fixes in the CAR plugin.

Implemented utilities to get rid of race conditions in plugins (now used in CAR plugin only)