twistedchecker fails when it encounters emacs backup files

[Richard Wall]

I ran it on my twisted branch and got this

(twistedchecker)[richard@zorin add-setup-1084552]$ twistedchecker twisted
Traceback (most recent call last):
  File "/home/richard/.virtualenvs/twistedchecker/bin/twistedchecker", line 10, in <module>
    Runner().run(sys.argv[1:])
  File "/home/richard/projects/TwistedChecker/branches/add-setup-1084552/twistedchecker/core/runner.py", line 320, in run
    self.setNameExceptions(args)
  File "/home/richard/projects/TwistedChecker/branches/add-setup-1084552/twistedchecker/core/runner.py", line 288, in setNameExceptions
    patternsFunc, patternsClass = findAllExceptions(path)
  File "/home/richard/projects/TwistedChecker/branches/add-setup-1084552/twistedchecker/core/exceptionfinder.py", line 83, in findAllExceptions
    findPatternsInFile(open(pathFile).read(), finder)
IOError: [Errno 2] No such file or directory: '/home/richard/projects/Twisted/branches/static-path-3765/twisted/web/.#static.py'

It should only examine actual python modules.