Allow spaces in CSS Name selector

I was doing `.click("[name='btn confirm normal']")` and it kept failing.
Allowing spaces in the find-element strategy made it work.

P.S. The 'magic' of this logic, might want some explanation in the docs.
Merge pull request #239 from jedi4ever/patch-1

Allow spaces in CSS Name selector
fixed request headers to work properly with phantomjs standalone - closes #225
v1.7.2