Added the ability to override resizing the images served up from the cache if PIL is installed.

* Add `--noresize` to command line argument so that the user could disable the use of PIL on resizing the poster/banner cached images. (ex: they need PIL for another python app but don't want PIL to be used for sb..)
* Corrected the etree import so it mimics how tvdb_api does (will try cElementTree first then fall back to the slower non-C ElementTree)