Restructured for optional content

Changed things around to ...
- Only import own copy of TEPP when needed
- Only import own copy of Invoke-SqlCmd2 when needed
Allowing borrowed content to only be imported when the original is
unavailable.
Updated the help test to support an exceptions list, that users can use
to exclude a function from the test where justified.
Updated psm1 to  support these changes
Updated psd1 to reflect change and sorted commands by name.