* Refactored BaseModel for efficiency
* Added plugin metaclass to keep track of plugin types
* Moved plugins to examples dir (in a previous commit)
* Simplified validation in parse_params
* Added convenience methods to mock requests in tests
* Changed help schema to use `.valid_parameters` instead of `.parameters`,
which was used in results to show parameters provided by the user.
* Improved UI
* Added basic parameters
* Fixed bugs in parameter handling
* Refactored and cleaned code
In index.html, there is a suggestion to try out the api with a link to "/api". Clicking that link results in a json error report - not ideal.
Instead, I added text suggesting that a use can find example api url's after clickgin "Analyse!".
