Upgraded gtk/libexiv2 to 0.14.0
Upgraded gtk/pango to 1.50.3
Upgraded gtk/pangomm to 2.46.3
Replaced http with https in the URL in some gtk build files
Cleaned up build options in several gtk pkg build files
Updated gtk buildlist
Added code to disable docs compilation in gtk/babl
Removed code to disable overlinking in gtk/gspell and gtk/gtk2
Fixed arch variable gtk/gst-plugins-base