Add protobuf conversion utils

New sub-package phonenumbers.pb2 includes the protobuf-generated
PhoneNumber class (as PhoneNumberPB) plus utility functions to
translate between that and phonenumbers.PhoneNumber.
Use syntax highlighting in the readme file.
Merge pull request #25 from ming13/readme-syntax-highlighting

Use syntax highlighting in the readme file.
Only include necessary parts of metadata

Taken from upstream r600.
Regenerate metadata skipping unneeded parts.
Merge branch 'dev' into python3

Conflicts:
	python/phonenumbers/phonemetadata.py
	tools/python/makefile
Fix some Py3K failures from mismerges