Update to post-review to fix issues when running with Python on Win32

Review Request #353 — Created April 7, 2008 and submitted

Review Board SVN (deprecated)
This is a general update to the patch posted in review #158, checkin r1211. This specifically updates the code to enable it to run on Python on Windows - mostly changing the quoting of p4 executable commands and dealing with the stripping of a carriage return that's missed in the regular expression check.

This update also includes a tweak to print out the review # (not at all critical, but a request from some of my users), and to deal more nicely with the case of not entering a changenumber when using Perforce SCM.
posted and updated reviews from my desktop windows box to our internal reviewboard server.