Fix migration of Python nodes
Migration path update
Update "Select Face" migration to retain element
Fix magn1571: indexing into string does not work properly
Resync custom node defintion if it is updated before open .dyn file
Function definition in custom node

- Formula node now compiles to a function definition node, so it can't
be used inside custom node unless we promote the function definition
inside custom node to global scope.
- AstBuilder._CompileToAstNodes() promotes the FunctionDefinitionNode
returned from node.BuildAst() to global scope by notifying the graph
sync data about the function def node and not adding it to resultList.
- Now Custom node supports CodeBlockNode with function definition and
the Formula Node.
Merge branch 'master' of https://github.com/ikeough/Dynamo into Migration
Re-enable zero touch UI

For the brave
Add more test cases for string indexing
Update migration of XyzAverage
Added support to load custom nodes for recorded tests
Merge branch 'master' into MAGN-3185
Return this instance from method returning void

Fixes http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-2334
Deprecate CreateRevolvedGeometry node
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into Migration
Migration path update
Update migration of GetFamilyInstancesByType
Update README.md
Update README.md
Update README.md