[CODE] Import paths are now relative instead of absolute in parsing/

Work in progress...

...just need to add some elements in RisFileParser._parameters and IsiFileParser._parameters.

Now, create some mother class to allow RIS as well.
Also, integrate more fields.

- Added some tests for Notebook

...now for some happy debugging.

Todo: incorporate the extracted ngrams and link them to the given document.

Added a Resource database object.

Allows parsing from various sources.