Fix initialization of gcrypt to avoid crashes if other libraries fail to do it so

https://bugzilla.gnome.org/show_bug.cgi?id=732475
Added 'category' and 'programming-language' to .doap file
Implemented flickr.photos.setDates API in flicksoup

This is needed to be able to set the posted date to the taken date.

https://bugzilla.gnome.org/show_bug.cgi?id=734193
New option in 'Misc' tab in settings: 'Use date taken as date posted'

https://bugzilla.gnome.org/show_bug.cgi?id=734193
Load DateTimeOriginal for 'date taken' from EXIF information

EXIF's DateTime changes whenever the file changes (e.g. edited) so it's
not a good value to use for the 'date taken' field. DateTimeOriginal
actually represents the moment the image was capture, so use that one.

https://bugzilla.gnome.org/show_bug.cgi?id=734193
Updated FrogrController to allow setting 'date taken' as 'date posted'

This is not 100% correct yet, because the current implementation assumes
that date and time extracted from the EXIF information is UTC, but that
does not have necessarily the case.

https://bugzilla.gnome.org/show_bug.cgi?id=734193
Rewritten comment explaining the problem with 'date posted' and UTC

In the end, I don't think there's a much better solution than just to go
for UTC, since many pictures won't have the TimeZoneOffset EXIF tag
anyway, and also because for sorting purposes in the photostream just
interpreting the date as UTC (even if it's wrong) should be enough.

https://bugzilla.gnome.org/show_bug.cgi?id=734193
Reorganized how settings are loaded and stored from/to disk
Move the 'Use date taken as date posted' option from Misc to picture defaults

Make it possible to define a value by default for every picture as is
loaded, as well as to define case by case values if needed.

https://bugzilla.gnome.org/show_bug.cgi?id=734193
Fixed issue setting inconsistent state for toggle buttons in details window
Fixed wrong translatable string in details dialog
[OSX] Stop using my own moduleset and use the upstream one from gtk-osx
[OSX] Build pango with --with-included-modules, to avoid problems when bundling
[OSX] Added GIO modules to frogr.bundle and point it from the launcher
[OSX] Build GTK+3 without gobject introspection
[OSX] Build librsvg without gobject introspection
[OSX] Build libxml2 before libcroco
[OSX] Updated README file, adding mention to 2 meta bootstrap modules
[OSX] Add libogg, libvorbis, libtheora, liborc and gst-ffmpeg as dependencies