Mono Support

Adds support for Mono, tested on OpenSUSE 12.2 with Mono 3.0.3; If required, I`ll look into adding support for Mono 2.x

I have added comments to UriIdentifier.cs and StandardWebRequestHandler.cs explaining the problems. If these could potentially cause security concerns, please let me know how and I can look into alternatives. That being said, these are the issues that needed addressing, so the tough part of finding them has been done, and these tweaks work on my server.