Update Table Component

- Updated existing table styles based on new table design
- Added new mixin for flexbox tables: `flex_table( {integer} $colCount )`
- Implemented 12-column `.flex_table` class
- Base styles are for mobile, with an override for a larger viewport
- Extremely thin implementation to allow for the component's use in various contexts
- Child class names consistent with those of `.table` for easy adoption
- Bumped bower version to 1.3.1

- [ ] review
Actually, after talking with Melanie, they are ditching borders on rows, keeping on only under the `.table_header`, so I will remove this altogether.