feature request: `checkout last`

[chriscorwin]

csc@6826-csc Tue May 22 10:34:19
~/Development/workspaces/mac_helios_workspace/finishline
   proj:  promos---2012-05-18---Friday
 branch:  CHG65843---add-new-pant-lengths-to-website

$ checkout master

This would save CHG65843---add-new-pant-lengths-to-website to a temp file, and run the normal checkout process.

Then:

csc@6826-csc Tue May 22 10:34:33
~/Development/workspaces/mac_helios_workspace/finishline
   proj:  promos---2012-05-18---Friday
 branch:  master

$ checkout last

...would look for a branch named last (which would be reserved in gitscripts new command) and if not found would look for the temp file with the last known branch name to check out.

Make sense?