Response to code review for GridLayout:

. Fixed spelling.
. Added comments on internal methods.
. Adopted the suggested internal name changes to improve clarity.
. Added UNDEFINED constant to public API to avoid making reference to Integer.MAX_VALUE in docs.
. Added final everywhere, then removed it.
. Make the Interval class package private so that it can be put somewhere more general later.
. Tidy code, removing maximize flag throughout.
. Remove last of allocations taking place during layout.
. Implement measureChild() etc.
. Added LinearLayout alignment compatibility mode, and made it the default.

Change-Id: I6a4ffa022d97d68138d1903d3830a20278815435
https://android-git.corp.google.com/g/#change,109891