Allow custom ignore parameter in LdaModel.save

[mattilyra]

In LdaModel.save the ignore list is explicitly passed to the parent method, making it impossible to add anything to that list. I propose that the ignore list be handled in the following way instead.

if 'ignore' in kwargs:
    kwargs['ignore'] = list(set(['state', 'dispatcher']) | set(kwargs['ignore']))
else:
    kwargs['ignore'] = ['state', 'dispatcher']
super(LdaModel, self).save(fname, *args, **kwargs)

[piskvorky]

Travis reports unittest fails for Python 3; we use six for dual compatibility.

For example, basestring in Python 2 becomes six.string_types for Py 2 & 3.

[mattilyra]

I somehow forgot that this was still open. I fixed it now and the tests pass. Upstream develop has been merged into the latest commit.

[piskvorky]

Looks good. Thanks @mattilyra !