Bug fixing environment variable translation

The following 2 use cases were broken. This PR corrects both:

__If an environment variable would result in more than 2 levels of nesting__
*Example*: Given an environment variable named ```THIS_IS_AWESOME```, configya would throw type errors due to a defect in how traversal was being handled.

__If a user attempt to access an environment variable using it's original name as a key__
*Example*: Given an environment variable named ```BACON_FLAVOR```, configya would not have a property named ```BACON_FLAVOR``` - breaking a unit test that specified this should be an allowed pattern.