dont convert css to xpath
driver can be queried for supported query formats and support for native css queries within a scope
fix failing specs due to invalid css
Selector remembers format, CSSHelpers, and drivers assumed to handle css
Add the CSSHandlers file
remove unused XPath.css conversion
change node and driver api to use find_xpath and find_css
cleanup Selector variable naming
tests dont need to be optional since native css support in driver is now expected
Merge branch 'css' of git://github.com/twalpole/capybara into twalpole-css

Conflicts:
	lib/capybara/query.rb
Remove superfluous comment