Enable spaces in paths by ensuring that all arguments are quoted.
When retrying with the DefaultVersionFinder, allow the exception to be known via the callback.
Merge pull request #53 from Ecno92/master

Fix for issue #38: Python 3.3: unable to locate initialization module
Merge pull request #51 from dmckeone/exception_on_retry

Allow access to the thrown exception, via the callback, with the DefaultVersionFinder.
Merge pull request #50 from dmckeone/master

Enable spaces in paths by ensuring that all arguments are quoted.