Fix WebUI gzip compression. Closes #1037.
Fix compilation with qt < 4.8.0. Closes #1043.
Sync translations from Transifex.
Rework fsutils class to only use Qt-style separators

  fsutils methods are guaranteed to accept strings with both native and qt-style separators and return strings with qt-style separators where appropriate
Update Preferences class

  Preferences class setters are guaranteed to accept string with both native and qt-style separators, getters are guaranteed to return string with qt-style separators