#879 Completions for JythonDataSource needs completion

[Jeremy Faden]

I just noticed

sc= getParam( 'sc', 'TS2', 'TRACERS Spacecraft', ['TS1','TS2'] )

will result in the completion TS2 even though it's pretty easy to add completions for all the enums. I've done this, but this really needs to be done for types other than String and Number.

[Jeremy Faden]

Also, constraints like

{ 'values': ['TS1','TS2'], labels:['TRACERS 1','TRACERS 2'] }

should be supported.