[MERGE/RFC] LocalTransport.abspath() should return a drive letter if the transport has one

[Ian Clatworthy]

Ian Clatworthy has voted resubmit.
Status is now: Resubmit
Comment:
the test needs to be skipped on non-Windows platforms - breaks the suite 
otherwise

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C041301c912d0%249e55cb10%24db016130%24%40com.au%3E
Project: Bazaar