Added libsigc++ 2.3.1.

	new file:   libs_devel/libsigc++/libsigc++-2.3.1-docdir.patch.xz
	new file:   libs_devel/libsigc++/libsigc++.build
Added glibmm 2.34.1.

	new file:   libs_devel/glibmm/glibmm-2.34.1-docdir.patch.xz
	new file:   libs_devel/glibmm/glibmm.build
Update parole to 0.4.0.

	modified:   video/parole/parole.build
Update firefox to 18.0.

	modified:   www/firefox/firefox.build