Layout Parameter Type and Value are incomplete

[AlexanderPico]

Do to pending CyREST bug (cytoscape/cyREST#100), the following functions only work with a subset of parameters that CyREST recognizes:

• getLayoutPropertyType
• getLayoutPropertyValue
• setLayoutProperties

I could fix getLayoutPropertyNames by switching to commandsHelp(), but these other operations are not available as commands, so they are pending CyREST fixes.

[bdemchak]

Layout Parameter Type and Value are incomplete #60