CodeMirror: XML mode

This is my XML parser, based on the original:

What's missing:

MIME types defined: application/xml, text/xml.

@author: Dror BG (deebug.dev[at]gmail.com)

@date: August, 2011

@github: https://github.com/deebugger/CodeMirror2

MIME types defined: application/xml, text/xml.