Add support for protocol version (Fx 36+ only)

Closes #18
3.9.0
Update README.md with protocol
Check for number to protocolString
3.9.1
Update prefs.dtd

localize protocol.label into Japanese
Update prefs.dtd

localize protocol.label and update cipherSuite.label for ja-JP
Merge pull request #19 from Cai0407/patch-1

Update prefs.dtd
Merge branch 'patch-2' of https://github.com/Cai0407/cipherfox into Cai0407-patch-2
Merge branch 'Cai0407-patch-2'