CP-221 Release wGulp 0.7.4

PRs contained in this release:

https://github.com/Workiva/wGulp/pull/108
https://github.com/Workiva/wGulp/pull/112
https://github.com/Workiva/wGulp/pull/111
https://github.com/Workiva/wGulp/pull/103
https://github.com/Workiva/wGulp/pull/114

Diff Between Last Tag and Proposed Release: https://github.com/Workiva/wGulp/compare/0.7.3...Release_0.7.4

How To +10/QA
-------------

```bash
# skip the following steps if you've already initialized the project
git clone git@github.com:Workiva/wGulp.git
cd wGulp

# do not skip these!
git fetch && git checkout Release_0.7.4
Run unit tests
```