Init project
Add main public API
Improve PostCSS#use tests
Update development dependencies
Add parser
Show file name in error message
Test nested at-rules
Move rules and decls list code to mixins
Change license to MIT
Refactor raw properties and mixins
Allow to miss toString() on fs.readFile return
Clean up parser tests
Add CSS stringify
Update npm packages
Rename Container#push() to append()
Clean up tests
Fast node defaults
Add inserts methods to Container
Clean up inserts code
Cleaner syntax to add new declaration