Module Refactor

Refactors modules into their own sub directory under CLI. This allows for a namespace to put utilities, helpers, and core CLI code outside of __init__.py. Ah, a place to stretch our legs.

* Moves modules from SoftLayer/CLI/*.py to SoftLayer/CLI/modules/*.py
* Moves code from SoftLayer/CLI/__init__.py to all these places: SoftLayer/CLI/core.py, SoftLayer/CLI/environment.py, SoftLayer/CLI/helpers.py

Note: If you're adding a new module after this is pulled, you should move it to SoftLayer/CLI/modules/