changes and fixes for post-Grasshopper 0.9.61 full compatibility. 

Includes:

- Grasshopper.dll is automatically added as a reference for scripting
- addition and removal of Inputs and Outputs is supported in the native Grasshopper ZUI way
- code input and out output stopped working. This is fixed
- code input and out output are now removable also via + and - ZUI signs
- several IO issues in deprecated (old) components were fixed. Also old components should keep on working properly
- GH_IO.dll deprecated iteration over chunks was removed
- registration of input parameters now via the Grasshopper SDK-suggested way
- floating editor could remain linked to a deleted component. This is fixed