add error handling for aborted requests for IE9

- when reading attributes from the XHR object from an aborted request in IE9 causes a breaking error. Namely  c00c023d.
- Added checks to see if the request has been aborted, and avoid reading the XHR attributes if it has.
Add XHR Reuse example test
Initialise properties on facade when calling open

Resets everything when calling open for a second time, fixes #29.
Add mocha test runner and initial test
Merge branch 'xhr-reuse' of https://github.com/peterjosling/xhook into gh-pages
Merge sondremare/xhook, #closes 29, IE9 abort bug (@sondremare)
updated docs, added initial tests - closes #20, removed version from distribution path