[TECH SUPPORT] LPS-29690 Css modifications do not apply

Hey Nate,

This ticket is coming from support. It's a regression bug introduced by http://issues.liferay.com/browse/LPS-25342 about Sass, and Jorge told me that you're the one who introduced Sass in the portal, so I'm sending this to you.

With that change, now only the modified files are compiled with Sass. Then, the customer is complaining that when changes custom.css file to add some styling and deploying, the changes are not applied to the portal.

The reason why they are not applied is because main.css file wasn't changed, therefore main.css won't be compiled, so the changes in custom.css won't be included in main.css (where the portal reads the css).

Alberto fix works this way:

1. Compile only the files that changed. 
2. Iterate all the files in the theme searching for imports to any of the modified files. If any file is found it will be included to the list and it will be recompiled. 
3. Continue with the process until all the files that are modified or contains imports are modified (this is a recursive process, because there might be some files containing imports that are imported in other files)

The thing is that I don't know if it's worthy to include all this logic or if it's better just to rollback changes in http://issues.liferay.com/browse/LPS-25342.

Thanks Nate!