pep8 of app_cfg
Moving fixed 'templates' to instance property, update doc

Signed-off-by: Nicholas Bollweg (Nick) <nick.bollweg@gmail.com>
using jinja2.TemplateNotFound for bad paths

Signed-off-by: Nicholas Bollweg (Nick) <nick.bollweg@gmail.com>
Changing TemplateNotFound Exceptions to match Jinja FSLoader style

Signed-off-by: Nicholas Bollweg (Nick) <nick.bollweg@gmail.com>
updated doc to reflect defaults
Added tests for PPL, refactored, and fixed issue with partial ordering of EP overrides
Fixed errantly removed logger