[MERGE] Add an optional 'token' keyword argument to LockableFiles.lock_write

[John Arbash Meinel]

John Arbash Meinel has voted +1 (conditional).
Status is now: Conditionally approved
Comment:
This is just giving Robert's +1 conditional vote since he voted on the 
ML rather than using BB.


For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C20070412053741.GE6345%40steerpike.home.puzzling.org%3E