Also:
. removed static import of R.styleable - this is non-standard
. removed final modifier from DEBUG flag,
this prevents the compiler from excluding the debugging code but
allows debugging code to be enabled externally
. added override to removeAllViews() as GridLayout needs to be notified whever hiearchy changes.
Change-Id: I2409289bce7c6638eff320ffd48a6c0704e77fa8