fix #5, update grid system
set global box-sizing to border box
update grid system
update test file and add class to display
reversed grid
Merge pull request #6 from rnarius/feature/grids

fix #5, update grid system
we got a mixin for that ...
add grid--flush to use grid without gutters
add grid size variations, update test file
Merge pull request #7 from rnarius/feature/grids

size variations for grids