Hot fix for:
1) Deleteing nodes which do not have inputs and output links (terminal nodes) and links attached to them.
2) Not causing terminal error when encourtering profile for which no link or node exists in network.
Correcting some issues with deleting nodes missing an input or output link.  As well elevation no longer gets set to '' when adding a new sensor.
Correcting sensor set to be set name and description to be nul, since name will be populated before creation if it is null.
Merge branch 'master' into dev
Merge branch 'dev' of github.com:calpath/scenario-editor into dev
Correcting Sensor Set spec to expect null name and description.
Correcting removing input/output links from a given node.