Handle common initialisms as the non-first word

[noamcohen97]

If a common initialisms was the prefix of the second word (or any word other the first one) of an identifier, it was treated as initialism even though the next rune was uppercase. e.g. "USER_IDENTITY".

This PR should resolve this issue

I have:

• Added tests covering the bug / feature (see testing)
• Updated any relevant documentation (see docs)

[coveralls]

coverage: 58.869%. remained the same
when pulling bbe0df8 on noamcohen97:fix_initialisms_bug
into a711ecb on 99designs:master.

[StevenACoffman]

Thanks! I really appreciate the clarification in the comments and renaming of variables.