Slight cleanup in the way command parameters are converted to forms
Slight cleanup in the way command parameters are converted to forms

Still a long way from a coherent API, though.

Closes #106

tzuhsiulin/prosemirror,jacwright/prosemirror,adrianheine/prosemirror,kiejo/prosemirror,ProseMirror/prosemirror-markdown,tgecho/prosemirror,bengler/prosemirror,salzhrani/prosemirror,tzuhsiulin/prosemirror,salzhrani/prosemirror,mattberkowitz/prosemirror,kiejo/prosemirror,mattberkowitz/prosemirror,adrianheine/prosemirror,tzuhsiulin/prosemirror,tgecho/prosemirror,jacwright/prosemirror,salzhrani/prosemirror,bengler/prosemirror,adrianheine/prosemirror,kiejo/prosemirror