Adjust marketplace to better utilize theme colors, fix widget title spacing

[thevoiceofzeke]

In this PR:

• Removed hard-coded colors from marketplace tabs (so other themes don't get red tabs)
• Added ng-styles to non-material DOM elements that leverage the current material theme
  • Note: These are inline styles, so I'm viewing it as a short-term fix :/
• Adjusted button appearance/layout in marketplace
  • We get to /apps by clicking "add more to home," so it makes sense that "add to home" should be the primary call to action for each marketplace entry
  • Accent color is only used in raised buttons (so it is a background color instead of text color) -- this will ensure better color contrast for some themes)
• Adjusted text of the expand widgets toggle to say what it actually does as simply as possible ("expand widgets")
• Adjusted spacing of widget titles to avoid clipping when text wraps
• Formatted marketplace controllers so indentation is less maniacal

Screenshots

[apetro]

"Research Project Resource Guide" is technically one character over our documented maximum title length -- but I'm not sure what one would do about that to comply with the limit? "Research Project Resources"? "Research Project Guide"? Maybe the title limit needs to be a little longer to embrace the reality of the long names of some things in our university world?

So I agree with the style tweak to avoid clipping, it's a good fix. Long thing titles continue to be a design challenge.

[apetro]

Inconsistent capitalization? Prefer sentence-case?

[thevoiceofzeke]

@apetro: It's written both ways at the moment because everything in md-menus is capitalized. I'm going to write a PR for frame that makes items in md-menus sentence-case as well (that would be consistent with google's guidelines).