Review and integrate prod-uisymbols branch

[charlesh88]

#188 Don't delete prod-uisymbols after this integration, I intend to keep updating this branch on an ongoing basis.

Have merged latest master branch into prod-uisymbols, and have modified and added art for e615 and e616 glyphs accordingly. The Google font symbols map has been updated.

Author checklist:

• Changes address original issue? Y
• Unit tests included and/or updated with changes? N/A
• Command line build passes? N/A
• Expect to pass code review? N/A

[larkin]

Review Checklist

1. Changes appear to address issue? Y
2. Appropriate unit tests included? N/A (No changes)
3. Code style and in-line documentation are appropriate? Y
4. Commit messages meet standards? Y
5. Project-specific information isolated to appropriate branches? Y

Integration Checklist

1. Automated build passing after merge? Y
2. No merge conflicts (or resolution trivial/obvious)? Y
3. All master branches up-to-date after merge? Y
4. Project-specific information isolated to appropriate branches? Y