A few doc comment fixups

A few doc comment fixups

* Remove some creation dates, they are not protected by GPL
* Remove duplicate @defgroup API
* Remove @ingroup from some @file doc comments on class files. It is not
  useful to list class files alongside classes in the doxygen module menu.
  Add @ingroup to some more class files that had @ingroup on their file,
  that was probably the author's intent.
* In PackedOverlayImageGallery, use the file comment as a class comment
* Don't put @defgroup and @file in the same comment. @defgroup makes the
  whole doc comment describe the group.
* Instead of putting AnsiTermColorer in two groups, use hierarchical
  groups.

Change-Id: If54f6e0b2bc1ea6de42045885cf836ee67b8e961