Mutation tests refactoring
Merge branch 'master' of https://github.com/DynamoDS/Dynamo

Conflicts:
	src/DynamoCore/TestInfrastructure/MutatorDriver.cs
Attribute class added
Merged few files from "Concurrent" branch for review
Included "SetTraceDataAsyncTask.cs" project in "DynamoCore.csproj"
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into NewAsyncTasks
Set some defaults.
Revert "Set some defaults."

This reverts commit 24e3ec40a9ffddc5c79fc6cbe5a32e28a00a9c1a.
Remove old RevitWarningSwallower.
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into NewAsyncTasks
Added documentation for CompileCustomNodeAsyncTask class
Added documentation to "DelegateBasedAsyncTask" class
Fix failures processor hooks.

By moving this call to setup the transaction manager, we get the
transaction manager's failure events to be properly handled by the
failure delegate.
Merge remote-tracking branch 'origin/master' into RehookFailureProcessor
Migrate lacing in MigrateToDSFunction methods.
Merge branch 'master' of https://github.com/DynamoDS/Dynamo
Merge branch 'master' of https://github.com/DynamoDS/Dynamo
@Benglin Here are some updates code according to your notes.

Brief changes description:
MutationTestAttribute was added to all mutation tests in order to distinguish Mutation tests classes from others in DynamoCore (it simplifies process of launching these mutation tests).
MutatorDriver class contains only basic methods for test launching, it also obtains all mutation tests from current assembly and runs them on the current workspace.
MAGN-4363: arc by start point end point start tangent
Merge branch 'master' of github.com:DynamoDS/Dynamo