Unit tests, fixes calculation of number size

[jmhummel]

Fixes number size calculation

Naming Rules and Data Types:

Numbers can be positive, negative, or zero. Numbers can have up to 38 digits precision. Exceeding this results in an exception.
Positive range: 1E-130 to 9.9999999999999999999999999999999999999E+125
Negative range: -9.9999999999999999999999999999999999999E+125 to -1E-130

Looking at this page in the documentation, I realized my previous implementation was incorrect, and 1 byte = 2 decimal digits. Which makes more sense, since "99" takes 7 bits to store. The other 1 byte needed holds the exponent.

• Adds multiple unit tests for each value type
• Updates CircleCI build node version to 8.10 (LTS)
• Adds .gitignore
• Added a CircleCI badge to the README, you'll likely want to change that in your fork to point to your CircleCI instead

[jmhummel]

@mcwhittemore

[mcwhittemore]

Thanks for the at mention. Merged and published in 0.3.1.