Save datasets with file name instead of whole path.
Save datasets with file name instead of whole path.

Using "f.name" in SymbolicDataset.register_dataset was causing Datasets to be
saved with their entire path intact in the Datasets folder (eg. saving
"/home/rmcclosk/..." would create subdirectories Datasets/home/rmcclosk/...).
Changing "f.name" to "os.path.basename(f.name)" fixes the issue.

Closes #183.

cfe-lab/Kive,cfe-lab/Kive,cfe-lab/Kive,cfe-lab/Kive,cfe-lab/Kive