Dynamo Update release 0.6.1

The next incremental release of Dynamo visual programming is out, with lots of fixes and shiny new tools.  

Undo/Redo now available:  yes, we know this has been a long time in coming and is a pretty basic thing.

Visualization in canvas (available in Vasari only):  By default, whenever you make any kind of geometric entity, Dynamo will create preview geometry in the Vasari canvas.  This is a lightweight, quickly regenerating temporary visualization that will only be active during the session, nothing is saved in the file and these are not true Revit elements.    Because Vasari is on a slightly different development schedule than Revit, it has a few additional tools available for that we can take advantage of.

Override Colors in View:  this node allows users to create arbitrarily override default colors of Revit families on a per-view basis.  You can use this to create your own analysis outputs, diagram relationships, or whatever you need color for.

View creation nodes:  Programmatically create section, axo, crop controls,element isolation, more.  In Revit, use them in conjunction with sheet creation and view placement nodes and they will update like any other good BIM element.

Package manager improvements:  Search for nodes is now instant (no commit needed).  Deprecation of existing packages is available, so you can remove existing nodes from search and indicate that you have a node that is no longer supported. We also have improved save functionality to allow for creating variations of existing custom nodes.

Raybounce node: this is a very general implementation of a ray casting tool, which is appropriate for doing all sorts of analysis or form finding.  Use it for glare studies, acoustic simulations, view analysis, and much more. Input a starting point for for the ray and its direction, get a list of objects that are hit and the xyz coordinate of the intersection of rays and elements

Check the readme for a full list of fixes and improvements.

Fixes
- Project to Face/Plane corrections
- many excel node fixes and performance improvements
- Python output improvements for integers
- Best Fit Plane Orientation consistency
- Conditional statements don't break formula node
- Custom node fixes
- Package Manager download fixes

New
- Undo/Redo now available
- Many UI improvements
- Visualization in canvas (available in Vasari only)
- Background and watch 3d can now draw from any node with geometric output
- Coloring preview geometry based on node selection
- navigation without with key commands
- navigation with onscreen commands
- View creation nodes: section, axo, crop controls,element isolation, more
- Sheet creation and View placement
- Override Colors in View
- Package manager search is now instant, no commit needed
- Deprecation of Packages
- Drop down menus sorted by name
- name inputs for levels
- better reference line/model line creation methods
- Model Text nodes
- Raybounce nodes