Parameter map

[jsbrittain]

Features

• Add support for parameter metadata
• Add dropdown box support on parameters
• Enable parameter linkage

Resolves #122 #174

To link a parameter:

• Build and launch the GRAPEVNE electron app (for build instructions, see https://grapevne.readthedocs.io/en/latest/getting_started/installation.html#developer-build)
• Click Get module list (after a few seconds, if none appear then go to Settings and reload defaults)
• Drag any two modules onto the canvas and join them together (some source modules do not accept inputs)
• Click on the receiving module and select the 'link' icon to link the parameter to the source module, the parameter value should update automatically when the source parameter is changed. Parameters can be chain linked between multiple modules, connected between core modules and sub-modules, and should be resilient to deletion of originating nodes.
• Linkage tests are included in end-to-end ('postbuild') tests.