Set all content of buf[PATH_MAX] to 0 upon allocation

Makes bt's that contain such buf's a little bit more beatiful.

Relevant Coccinelle patch:

@@
type T;
identifier tmp;
@@
- T tmp[PATH_MAX];
+ T tmp[PATH_MAX] = {0};
Updated Catalan translation
Merge pull request #776 from josepvm/master

Updated Catalan translation (fixed a single minor error I've discovered just now, sorry)
Allow compilation without usermanual sources

... and fix the release script accordingly. It only used to work due to
a typo.
Prepare for a little nicer code formatting
Don't put a space after casts
Run style beautifier, this time using clang-format
Ignore some more files when formatting code
graduated density: fix gradient mouse move when zoomed in.
OSX HiDPI: fix most places, central DR view is still broken
OSX HiDPI: revert changes to map.c from last commit

since osmgpsmap will draw pixelated map anyway
OSX HiDPI: fix logo in bg of zonesystem
OSX HiDPI: fix slideshow view
OSX HiDPI: return correct mipmap level for HiDPI screens
OSX HiDPI: fix central DR view
OSX HiDPI: update package building instructions
OSX HiDPI: add config option and disable for old cairo