unfinished attempt at issue #19

- doesn’t work yet
- tests are broken
- not operator seems to break due to xmldom
working in most browsers, still broken in IE

IE’s DOMParser’s parseFromString method rearranges attribute order
which messes up this whole feature.

They consider this a feature, not a bug, despite every other browser
doing the opposite:
http://stackoverflow.com/questions/4445153/javascript-parsefromstring-ch
anging-order-of-elements-in-xml-doc

Thanks IE.

Possible solutions:
- Parse the document using xmldom client-side?
- Some crazy regex?
- Send angry mob to Microsoft?
docs update
disabling boolean logic for IE
Merge pull request #22 from kethinov/booleanlogic

implementation of #19