Add -hideAnnotation parameter to doclava.

Basically this is -showAnnotation, but for the opposite use.
Specifies Java annotations that should be treated the same as "@hide"

Test: Sadly there are no unit tests for Doclava, however, this change
builds and treehugger should ensure that Doclava's existing usage
still works.
Change-Id: I76fe6d74eff2db08f65f992ded0cae9144fc31a1
4 files changed