- Flexbox responsive behavior fixed with specific .col-{breakpoint} classes now added
- Dropped the make-col mixin in favor of a column-basics placeholder that we can extend across our grid infrastructure
- Updated docs to use required .col-xs-12 (as a safeguard for when folks enable flexbox mode--this isn't necessary in default grid mode)
- Update flexbox grid docs to include responsive docs, tweak some other bits too

flip things around again, no more base class, try out some new stuff to keep responsive flex grid working

Revamp grid classes to require .col base class and improve flexbox grid classes with auto layout via flex: 1

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Signed-off-by: O'meid <public@omeid.me>

doing so fubars the grid column rounding (in safari at least) and causes layout problems

Breakpoints and container widths are now defined as maps.