Make CSS files/path configurable

Added config options to readme

corrected order of assert params

added another test css
Format code

Format code
prevent catching callback test errors
changed test size to only include header nav
fixed fixtures
Fixed tests

 - strip whitespace before comparing styles
 - changed tested size to 320 x 70 to only include the header
some code formatting
Merge pull request #22 from bezoerb/ConfigureCssFolder

Configure CSS folder/file
change penthouse test to critical css test
Merge pull request #26 from supabok/master

Change penthouse test to critical css test
Merge pull request #25 from micahblu/master

CSS Images fix
Update to Penthouse 0.2.5 to addr raised issues
Release v0.1.6.
Resolved merge conflicts