Update composer.json and README.md so I can stick this on Packagist
Fix CSS filter
Added boolean handling for the checked attribute

this allows to conditionally generate the checked attribute on radio buttons or checkboxes.

example jade code:
input(type="radio", name="test", value="1", checked=checkedOne)
input(type="radio", name="test", value="2", checked=checkedTwo)

if $checkedOne is set to a truthy value, the checked attribute will be added to the generated php otherwise it is omitted completely.
Merge pull request #9 from cryptix/patch-1

Added boolean handling for the checked attribute.
fix each/else prefixed with `-` and spaces,
fix data-* attributes escaping,
modify some tests, add test for checked attribute.
cast more attrs (checked, selected, readonly, disabled) as booleans.