Layoutlib: add support for ITextServicesManager.
This include a fix in layoutlib_create to properly handle
delegating a static method of an inner class (was broken and
only worked on non static method).
Added a few comments here and there to *_Accessor classes so
that it's a bit more obvious what they are for and how they are
used.
Change-Id: I186ce33236e4de08d0205f75fb8d20d74c92da34
6c465bbe80