OSX: fix DPI detection
fix possible use of uninitialized value in previous commit
[l10n] Update Spanish translation
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
Merge branch 'master' of https://github.com/darktable-org/darktable