Snap to ends of lines if node Id properties are present

[geographika]

Currently, if a user doesn't have a vector node layer switched on, and they snap to the end of a line, an edge Id is returned.
This will require a line to be split if the drawn lines are required for routing - even though the new line snaps to a node.

This pull request allows node Ids to be picked up from the line if a drawn line snaps to the end.
A new config property has been added to the tool to set which properties of a line feature contain the node Ids:

  edgeLayerConfig: {
      startNodeProperty: 'NodeIdFrom',
      endNodeProperty: 'NodeIdTo'
  },

If this is set then node Ids from the line will take priority over the line id.

The node Ids will have to be added as properties to the line vector layer. This can be set in the serverOptions for a WFS layer in the JSON layer config file:

  {
      "layerKey": "NETWORKEDGES_WFS",
      "layerType": "wfs",
      "idProperty": "ObjectId",
 ...
      ],
      "serverOptions": {
        "propertyname": "ObjectId,IsConnected,NodeIdFrom,NodeIdTo"
      },

CpsiMapview.mp4