[build] generate a banshee-1 launcher per platform
[build] generate a banshee-1 launcher per platform

Moved the old banshee-1.in launcher to banshee-1.linux.in,
and added a Darwin launcher, banshee-1.darwin.in. Depending
on the host type at configure time, banshee-1 will be generated
from either banshee-1.linux.in or banshee-1.darwin.in.

Also fixed pango to include basic-atsui, and work around some
strange build ordering.

bl8/bockbuild,BansheeMediaPlayer/bockbuild,bl8/bockbuild,BansheeMediaPlayer/bockbuild,mono/bockbuild,mono/bockbuild,BansheeMediaPlayer/bockbuild,bl8/bockbuild