first pass at vision
Add support for Sass and SCSS.
Fixes for Sass/SCSS converters.
Allow users to specify options for Sass.
Consolidate into one master 'Sass' converter.
Build Sass configuration options.
Don't allow path traversal or syntax overrides.
Does not allow caching.

This was done to prevent putting the .sass-cache folder in bad places. Needed? cc @benbalter.
Make sass a runtime dependency.
Add docs for Sass conversion.
Allow caching in unsafe mode, but disable in safe mode.
Add 1.4.3 release post by @BenBalter for master branch.
Update History.markdown with 1.4.3 release.
Require Liquid 2.5.5 <= x < 2.6
update dat gemspec
Update history to reflect merge of #1943 [ci skip]
Forgot #1943 in the line, whoopsie
Update history to reflect merge of #1949 [ci skip]
Make doc menus more reusable
fix full path leak to source directory when using include tag