Removing casing to characters after a number that are followed by a separator (issue #77)

[JCrandall101]

In this PR

Based on issue #77 for the following comment

The following example the returns the expected: Expected: b2b_registration_request -> b2bRegistrationRequest Received: b2b_registration_request -> b2BRegistrationRequest

Assumptions:

• If a letter proceeded by a number is followed by an underscore or dash, the letter should not be upper cased

index.js

• Reordered the replace functions to be able to check for separators
• Added ternary function to check if the character after the replace value is a underscore or dash and only changing case if it is not

  test.js

• Added 4 tests for the example string

Fixes #77