Remove the old README.

Change-Id: I867960f48c3f3b5a1b868c764af185c048196690
More doc updates.

Create doc/source/dev/ directory, and add several files that got
accidentaly ignored because they were under doc/source/api/.

Also move some files from doc/source into doc/source/dev to clean up the
base doc dir.

Change-Id: Ief9777216db82ec3be32b7a73e2d268a3a973ef8
Merge "More doc updates."