Ignore spyder project files in .gitignore
stub for multiascii test in MosImporter
Implementing multiple datasets for importer.

This is needed for the Mos/biokine multiY ascii files.
The firts passes check_first_multiline_dataset.
Mos Importer working also for multiY ascii files.

The importer now has a datasets property, which is an array to all the datasets that were loaded. The array always contains at least one element.