Fixed format of AppData file
Don't disable video uploads  depending on the platform

Allow disabling video uploads at configuration time, and look for
GStreamer only if the feature is going to be enabled (by default).
This should make easier to build frogr in other platforms other
than GNOME (e.g. OS X) that still have GStreamer available.
Reorganized configure and updated the configuration summary
Stop using libsoup-gnome to allow using the default proxy

Since libsoup 2.34, there's no need to use libsoup-gnome (which is
now deprecated) to use the system proxy, so we don't need to include
this headers nor to link against this library anymore.
Don't use soup_session_async_new() with recent versions of libsoup

This function has been deprecated in favour of soup_session_new() in
libsoup 2.42, so don't use it anymore for newer versions.
Add -DSOUP_DISABLE_DEPRECATED build flag to debug builds
Remove the option to explicitly enable/disable the default proxy

Since libsoup 2.34, any SoupSession will automatically pick the global
configuration settings for the system, so this is not needed anymore.
Updated screenshots for connection settings
Remove translated text for the GNOME proxy option