Genre translations

There is a branch for genre translation but it seems to be to complicated and dead for 6 months.

**I believe genre translation should follow these basic rules which are followed in videodb:**
* Translations should be in lang files, just like any others.
* Translations should be applied in view layer (templates)

**What has been done:**
1. Added genre translation for English, German, Spanish, French and Polish languages. Other languages use English names.
2. Updated function out_genres() in core/output.php. It seems to be the only place in code (besides templates) that is required for full genre translation.
3. Updated all templates

**What can be done:**
1) Translation labels are direct genre names (Action, Horror). It can be changed to use prefix, for example: genre_Action, genre_Horror.