[MERGE] optionally install tbzr binaries with bazaar binaries on Windows

[Ian Clatworthy]

Ian Clatworthy has voted resubmit.
Status is now: Resubmit
Comment:
markh indicated on IRC that he is resubmitting this.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C48746590.0305560a.619b.fffff1ce%40mx.google.com%3E