Merge all bidsapps to a single bidscoin bidsapp

[marcelzwiers]

It is very inefficient and it would cause fragmentation if BIDScoin's bidsapps would all be distributed as separate apps. A better alternative would be to group them all under the bidscoin umbrella, e.g. like this:

bidscoin bids_dir output_dir level deface [..]
bidscoin bids_dir output_dir level slicereport [..]
[..]

[marcelzwiers]

Dropping the idea because it doesn't look nice when the key action is only the fourth input argument