Add comment parser
Add split package dependency
Add minification to Compiler
Minify integration tests

Given that the default SCSS indentation in the sample files is different
from what the current printer produces, it's easier to just minify both
files and compare the content.
Support comments
Add parser for grouped selectors

For example "h1, h2, h3"
Fix types import
Update README with current progress
Add comment parser specs
Remove dead code