Added files nl.py and tests/nl-test.py

These are going to hold templates, similar to those for CE, but with a focus
on using the SimpleNLG JSON interface.
Merge branch 'master' into prototype-nl
Added an rdflib namespace for PROV in prov.py

provglish.prov.PROV is an rdflib namespace for "http://www.w3.org/ns/prov#"
Added provglish.nlg_tools module

This module (which for now remains without automated testing) contains the
settings for nlgserv as well as the function for calling it.
Added the first natural language template to the system

provglish.nl._ag_der_ent_by_act_template generates sentences like
"John baked a cake." where the cake was derived by the activity baking,
where the activity baking was associated with the agent John.
Added the prov namespace to the graph when loading the PROV ontology
Corrected the references to RDF as a namespace to rdf
Added a collections template

The system can now enumerate the contents of collections.
Added branch limitations to .travis.yml

It doesn't need to build on CI unless it's testing or master.
Changed the name of the package in setup.py to "provglish"

Previously it was capitalised, and looked weird.
Ammended the nlgserv dependency to reflect release of nlgserv-0.1.0
Added an NL template for Entity
Added an NL template for Activity
Removed a print statement that had become unnecessary.
Added activity_start to the NL templates.
Added NL template for activities with an end time.
Added NL template for generation
Added NL template : generation_activity
Added NL templates for Usage and Usage-Entity.
Added NL template for Communication