Add methods to Parcel for bool and char and byte

We lift these to int, but handling the details of that here will be better
than having AIDL generate casting code all the time.

Test: unit tests pass
Bug: 24981507
Change-Id: If6aa33ab5fe365dd237136a95c5d9a702af41d15
Signed-off-by: Casey Dahlin <sadmac@google.com>