restmod: adds _opt parameter to $url methods
url builder: improves url appending and adds extension support.
model builder: puts renaming configuration in builder
config: sets the src scripts load/concat ordering explicitly.
Makes setting the builder factory a call to the model builder.

This finishes cleaning up the config stage methods an closes #18.
This also removes the attrPrimary builder method.
refactors lib structure
improves core code documentation
improves general error reporting

closes #14
bumps version