More comments in travis script
Temp removal of example test
Update .travis.yml
Adding new LEMS elements required for Gap junctions:

Tunnel, InstanceRequirement, IndexParameter, ComponentRequirement
NOTE: only adding these to internal data model so NML2 comp type definitions can be read in; PyLEMS will throw an error if they are used in a Component in a model!
Merge branch 'master' into development

* master:
  Adding new LEMS elements required for Gap junctions:
  Update .travis.yml
  Temp removal of example test
  More comments in travis script