Fix Bug and Add Test Cases

[tstinebaugh]

While poking around this repo, I noticed the utils functions were mainly untested, so I added a few tests to increase coverage. I also found a bug in the add_reflection method where the default bgcolor was missing a 0 to be a true hexidecimal value.

[richardbarran]

Hi! Thanks for the MR and for spotting the bug with the color code.

I have a couple of suggestions/requests:

1. I suggest that in your local repo you add your new code to a new branch (not master). It makes it harder for the reviewer (me) to checkout and test your branch on my own PC as I already have a master branch.
2. The CI unit tests have failed. I strongly suspect that it's because of the sys.path.append statement in the unit tests; this should never be necessary. There must be a broken/incorrect import statement somewhere else in the codebase.

I look forward to hearing from you!