[build] add 'make update-docs' top-level target
[build] add 'make update-docs' top-level target

Also add merge-docs target that pulls any edits the user has done in
Monodoc and merges them, ready to commit or submit as a patch.

dufoli/banshee,mono-soc-2011/banshee,babycaseny/banshee,stsundermann/banshee,Dynalon/banshee-osx,GNOME/banshee,Carbenium/banshee,Dynalon/banshee-osx,arfbtwn/banshee,babycaseny/banshee,stsundermann/banshee,arfbtwn/banshee,lamalex/Banshee,babycaseny/banshee,dufoli/banshee,lamalex/Banshee,Dynalon/banshee-osx,ixfalia/banshee,Carbenium/banshee,Carbenium/banshee,arfbtwn/banshee,directhex/banshee-hacks,mono-soc-2011/banshee,Carbenium/banshee,arfbtwn/banshee,directhex/banshee-hacks,petejohanson/banshee,dufoli/banshee,allquixotic/banshee-gst-sharp-work,mono-soc-2011/banshee,babycaseny/banshee,GNOME/banshee,ixfalia/banshee,petejohanson/banshee,allquixotic/banshee-gst-sharp-work,stsundermann/banshee,babycaseny/banshee,dufoli/banshee,directhex/banshee-hacks,Carbenium/banshee,Dynalon/banshee-osx,dufoli/banshee,ixfalia/banshee,allquixotic/banshee-gst-sharp-work,GNOME/banshee,arfbtwn/banshee,mono-soc-2011/banshee,GNOME/banshee,lamalex/Banshee,Dynalon/banshee-osx,Dynalon/banshee-osx,dufoli/banshee,dufoli/banshee,directhex/banshee-hacks,stsundermann/banshee,Dynalon/banshee-osx,stsundermann/banshee,ixfalia/banshee,mono-soc-2011/banshee,ixfalia/banshee,stsundermann/banshee,GNOME/banshee,Dynalon/banshee-osx,GNOME/banshee,stsundermann/banshee,petejohanson/banshee,dufoli/banshee,allquixotic/banshee-gst-sharp-work,petejohanson/banshee,ixfalia/banshee,arfbtwn/banshee,ixfalia/banshee,arfbtwn/banshee,directhex/banshee-hacks,allquixotic/banshee-gst-sharp-work,lamalex/Banshee,stsundermann/banshee,GNOME/banshee,babycaseny/banshee,petejohanson/banshee,ixfalia/banshee,arfbtwn/banshee,GNOME/banshee,babycaseny/banshee,lamalex/Banshee,Carbenium/banshee,petejohanson/banshee,mono-soc-2011/banshee,mono-soc-2011/banshee,directhex/banshee-hacks,allquixotic/banshee-gst-sharp-work,babycaseny/banshee,lamalex/Banshee