Updated JavaScript Git pre-commit hooks to exclude minified files.

- Even though they shouldn't contain invalid statements, ignore them.
  The issue is with the source code anyway.
Refactored scanning of invalid source code for JavaScript pre-commit
hook to a single utility function.
Refactored Git hook extension support functions to common file.

- The "extensions/support.sh" is mean to be a common place for
  functions shared across all Git hooks.
- Each Git hook loads the "extensions/support.sh" script by default
  now.
- The JavaScript, Pry, and RSpec scripts all shared the same detetion
  code and is now located in the "extensions/support.sh" script.
- IMPORTANT: This will require installing/linking and re-
  initialization of all Git repos to pick up the new
  "extensions/support.sh" script.