Remove colorize depedency

[thomasrockhu]

Issue with colorize's license, so removing in favor of overloading String

[codecov]

Codecov Report

Merging #94 into master will decrease coverage by 1.57%.
The diff coverage is 90.00%.

@@            Coverage Diff             @@
##           master      #94      +/-   ##
==========================================
- Coverage   93.51%   91.93%   -1.58%     
==========================================
  Files           1        1              
  Lines         339      347       +8     
==========================================
+ Hits          317      319       +2     
- Misses         22       28       +6     

Impacted Files	Coverage Δ
lib/codecov.rb	91.93% <90.00%> (-1.58%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e0b8889...045c296. Read the comment docs.

[AlexWayfer]

I suggest to use Paint, I see it's under MIT license.

[thomasrockhu]

Thanks here @AlexWayfer, I'm going to merge this in as we don't need that complex of a color package. If that changes, I'll keep Paint in mind.