Add support for grammar in js message parsing
Atached patch tries to resolve this:
- make jqueryMsg understand GRAMMAR. Depend on the patch at Bug 33653
- Make SITENAME with value mw.config.get( 'wgSiteName' ) available in parser without the need of module users explicitly adding it.
- mw.language get convertGrammar, can be overridden per language as in php
- Make global variable wgGrammarForms available at js by adding to ResourceLoader default variables.
- Language.php get a method to filter wgGrammerForms for the current contentLanguage.
- Qunit tests
Not committing the code now, because core code is in 'slush'