Merge pull request #94 from wkerzendorf/general/fix_coveralls

Fix coveralls
started implementation of the complete tests (running whole TARDIS)
a simple test for TARDIS full run. much more to be implemented
a simple test for TARDIS full run. much more to be implemented
simplifying the full tests
added simple atomic dataset test + some documentation
added testing documentation to index.rst
added testing
working tests now for the full model