Upgrade to Sass 3.3, specifying explicitly

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Add Bourbon Sass mixin library

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Add Bitters scaffolding for Bourbon-based projects

To be removed later.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Comment out Bitters scaffold @import until needed

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Add modal dialog to display Export formats

Integrate angular-modal and provide basic styling (based on Bourbon
Refills recipe). Modal dialog lacks actual content, media query
support.

User Story # 5504

Signed-off-by: Alex Coles <alex@alexbcoles.com>