Adding column layout according to Material mockups:
- Maximum of 3 columns in "web" layout, with 360px fixed width columns, 40px gutters and excess padding left and right.
- 2 columns in "tablet" layout, with variable size columns and 24px gutters.
- 1 columns in "phone" layout, with 16px gutters.
Merge pull request #465 from sgomes/material-sprint

Adding column layout according to Material mockups: