Added *storm project configuration directory to gitignore
Added greater than and lower than assertion methods to css() assertion

Usage:
Expect value to be greater than 100px: css('.selector', 'property', '>100px');
Expect value to be lower than 100px: css('.selector', 'property', '<100px');
Improved declaration of comparisonOperator
Replaced parseInt with parseFloat (you might use like 0.3em)
Fixed doc block
Added comment on %, em, ... values
Merge pull request #39 from mdix/master

feat(assertion): added greater than and lower than assertion methods to the css() assertion method