Raise an exception if the include_properties file is missing
Load an additional properties_include from the http parameters.

This allows, for instance, be able to set different colors when running in full screen mode:

http://localhost:3000/liveb/0_app_core/?include_properties=black.yml
Fixed comments in README.md about include_graphs and added documentation for include_properties
Additional comment in README for the include_properties param
Merge pull request #68 from keymon/PR59-fixes

Brief smoke test was successful.