Added British English translation
Add French translation
Use more modern memory-freeing functions.

* src/gui.c (load_channels_from_config, cb_quit): Use
g_slist_free_full.
* src/pixpack.c (pixpack_destroy): Use g_clear_object and
g_clear_pointer.
* src/prefs.c (prefs_cancel_cb): Likewise.
* src/view.c (tele_view_free): Use g_clear_object.
* configure.ac (PKG_CHECK_MODULES): Require glib-2.0 >= 2.34 for
g_clear_pointer.
* src/gui.c (load_channels_from_config, cb_quit): Cast channel_free
to GDestroyNotify.
Reorder functions to allow making more of them static.  Remove some
prototypes for non-existent functions.
Corrected tags in Danish translation
Added Brazilian Portuguese translation for help file
Enabled Brazilian Portuguese translation for help file