Add support for analyzing SASS files

[macbre]

Resolves #3

[kangax]

How would I use Sass file when running analyze-css as command line? Just giving it --file errors out. I tried --preprocessor sass but it didn't work.

[macbre]

@kangax, the preprocessor is selected based on the file extension. Simply pass style.scss as --file option.

[kangax]

That's what I did but nope:

> analyze-css --file app/assets/stylesheets/_base.sass
Error: CSS parsing failed: missing '{' @ 2156:1

[macbre]

analyze-css uses node-sass npm module and it only supports files with SCSS syntax

[kangax]

That's strange. According to one of their issues:

"Once #324 has shipped we'll have pretty much automatic support for .sass files thanks to https://github.com/hcatlin/libsass/pull/181/files by @mgreter."

In any case, it would be great if analyze-css could parse .sass files, as I know a lot of people still prefer that (original) syntax.

I can open a new issue.

[macbre]

@kangax, thanks for looking into this. Please open a new issue to support *.sass files as well. We may need to upgrade node-sass version used by analyze-css

[kangax]

Opened #79 Thanks!