Need to import toscawidget to use bioscript command line tool

[yjarosz]

Bioscript command line tool should not import any tw stuff, but this is the only way at this moment to get back the options for any list fields (assembly, radiochoice, singleselectfield, ...).

One way to prevent this is to create an optional mapping attribute in the plugin, such as (FileConvert):

info = {
        'title': 'Convert file',
        'description': 'Convert a file to a different format',
        'path': ['Files', 'Convert'],
        'output': FileConvertForm,
        'in': in_parameters,
        'out': out_parameters,
        'meta': meta,
        'mapping': mapping}
in_parameters = [{'id': 'infile', 'type': 'track', 'required': True},
                 {'id': 'to', 'type': 'list', 'required': True},
                 {'id': 'dtype', 'type': 'list'},
                 {'id': 'assembly', 'type': 'assembly'}]
mapping = {'to': ['bedgraph', 'wig', 'bed', 'sql', 'gff', 'sga', 'bigwig'], 
                   'dtype': ['quantitative', 'qualitative']}

Then the form will be::

...
to = twd.HidingSingleSelectField(label='Output format: ',
        options=mapping['to'],  prompt_text=None,
...