Changed columns to always have consistent padding, row to use negative margin to make space for last columns padding
Updated css url, added nested columns example, changed where borders are applied to show content area of columns
Added $body-margin configuration variable, default is 8px (same as most browsers)
Added $horizontal-spacing, $vertical-spacing variables; replaced $spacing with horizontal/vertical equivalent
Added one-of-one column size
Merge pull request #29 from jmfee-usgs/flexible_grid_updates

Flexible grid updates