Changed deprecated wfMsg method where possible.
Most of log entries are now displayed using wfMessage method what fixed language issues when using StaffLog. Entries concerning user renaming or status changing are not translatable since they are inserted to a database as string into a comment field.
Removed unnecessary inLanguage method from chain
Removed unnecessary global wgLang
Merge pull request #1323 from Wikia/CE-100

Changed deprecated wfMsg method where possible.