Improved core documentation, improved interface.
Improved core documentation, improved interface.

* Some functions return self now to make test functions more concise.
* Documentation of TestResult object was added (the class itself had
  no docstring previously).

ucrcsedept/galah-interact-python,galah-group/galah-interact-python,ucrcsedept/galah-interact-python,galah-group/galah-interact-python,galah-group/galah-interact-python,ucrcsedept/galah-interact-python