ajax() was sending to the wrong host sometimes

The function ajax() was sending to the host window.location.host even if
the function was called with another host in the URL.
$.get() was appending a '?' even if no data

The function $.get() was appending a '?' to the URL of the request even
if there was no data to send using GET. This could possibly lead some
Node.JS websites which did not expect GET parameters to return an error.
Added function $.toDOM

Added a function allowing to parse a raw HTML document into a DOM
document.
Fix for coinurl

Now works with Ghostery and other anti-tracking tools, also it is faster
Example links:
http://cur.lv/8wzpa
http://bit.cur.lv/frvgfdf-gdfg451dfg,
Merge pull request #490 from devnoname120/cur.lv

Fix for coinurl