Parse metadata lines via a formal grammar.

And a parser generator.

Refs #1996
Use a formal grammar and parser generator for script metadata.

Merge of branch 'parser'

Fixes #1996
Use syntax that doesn't confuse my IDE (Eclipse/JsDev).
Update the parser to detect @noframes.

Refs #1859
When @noframes is set, only inject into top-level windows.

Fixes #1859
Do not install scripts from Sync without download URLs.

(They shouldn't be there in the first place.  But, in case.)

Fixes #2014
Delete corresponding temp files when a script source tab is closed.

Refs #2017
Remove unused error.access-violation string.

And update all translations from babelzilla.org .

Fixes #2020
Add-ons Manager: only force sort User Scripts.

Fixes #2021