Merge pull request #167 from mtwebster/mtp-mounts-sidebar

Support fuse/mtpfs mounts (like tablets, phones) with the diskfull sidebar indicator
Merge pull request #157 from mtwebster/breadcrumbs

Altering shape of pathbar/breadcrumbs 'buttons'
Add combo box to sidebar to allow selecting Places or Treeview.
Make the places/tree sidebar state non-global.

i.e.  You can now select tree view in one Nemo window, and Places
view in another.  The last selected mode will be the default upon
the next launch of a Nemo window.
Prevent warnings from gtk because we usually end up destroying the
tree/places combobox before its internal callbacks can finish.
Use the treeview for mouse tracking widget, the view toggler throws
off calculations for hover-tracking over sidebar categories.
Zoom:  Tear out existing zoom in/out/normal buttons and handler code.
Add nemo-statusbar.c, .h
Cleanup, fix makefile, test
Moved statusbar, to fill entire window, initial construction of
nemo-status-bar