shell bugfixes, dashboard work, HACKING updates

Patches applied:

 * walters@rhythmbox.org--2003b/rhythmbox--mainline--0.7--patch-155
   various shell bugfixes, jump to song added via cmdline, and more debug bits

 * walters@rhythmbox.org--2003b/rhythmbox--mainline--0.7--patch-156
   work with session management (Matt Hughes)

 * walters@rhythmbox.org--2003b/rhythmbox--mainline--0.7--patch-157
   HACKING update

 * walters@rhythmbox.org--2003b/rhythmbox--mainline--0.7--patch-158
   better dashboard support (Lee Willis)