Use 'Neutron' in place of 'Quantum'

bug 1201596

All usages of the Quantum codename have been replaced with 'Neutron' or
other periphrases.
This does not apply to references to Quantum 1.x, as well as some samples which
are in the source code tree but not used anymore.

Patched to address Akihiro Motoki's capitalization edits.

Change-Id: Ie6b0a5f82587e32737c975b3748573a6d6ce3945