Adding _site to gitignore
Adds --require switch to allow user specific config

This will allow people to configure bundler, sass plugins, special
configurations, etc.

refs: #54
Deprecates --compass-with-config

I knew that was a bad decision. --require will be a lot simpler

refs: #54
Parses and ignores @import statements

Users will need to run csscss on those specific files.

This also fixes a bug where comments were being merged with selectors.

refs: #41, #57, #58
Formatting the switches a little
Cleans up some require/abort lines
Adds an experimental flag to ignore sass mixin declarations

Users can now do this with --ignore-sass-mixins.

This is a heavily requested feature. Some users don't care about
duplication coming from sass mixins. So this will inject a special
comment before/after the properties from the mixin and the parser will
ignore it.

This will mess with reporting selector line numbers if I implement that
in the future.

I'm not sold on this being the default yet.

refs: #25, #59
Bumping version for 1.3.0 release
Updates README with --ignore-sass-mixins info
No need for such a long example
whoops
Fixes bug where --ignore-sass-mixins isn't respected in @imports

There is a `@children.empty?` edgecase that I can't recreate in the
tests but I'm seeing on a private codebase. It would be nice to
red/green test that bit of the conditional.

refs: #62
Bumping version to 1.3.1
Fixes attribute parsing bug where comments include braces

Also refactored out the dynamic bit in favor of present?/absent? logic.
Slowly getting the hang of those conditionals.

refs: #29
Adds ruby-version

This is rvm and rbenv agnostic
Added blurb on why csscss doesn't remove duplications
Add tests for empty nested rulesets.
Require at least one child ruleset.
Added contribution guidelines
adding the validation for single special character in attribute #70