Merge pull request #9 from mholden8/master

Fixes #2, Fixes #4 created a standard transform buffer node that is usable through the Transform Recorder logic.
Fixes #10: Transform Buffers can be dragged-and-dropped into Slicer, and the node names reflect the file names.
Fixes #12: Messages are added when the "Add Message" button is clicked, not when the "OK" button is clicked after the message is typed.
Added transform buffer storage node for saving the transform buffer with the scene. Transform buffer cannot be read with the scene yet. It must be imported separately.
Added functionality to read in transform buffer node via scene file (ie transform buffers can be loaded with the scene).
Fixed memory leaks associated with loading transform buffers. Renamed transform buffer "Save" button to "Export".
Moved module to "Perk Tutor" category.
Merge pull request #15 from mholden8/SaveLoadScene

Fixes #13: Transform buffers save and load with scene.
Use transform buffer modified times to control widget refreshes, instead of refreshing every 10ms.
When the buffer is modified, provide more specific information about what aspects of the buffer are modified. Handle this information in the widgets and update appropriately.
Merge pull request #17 from mholden8/ModifiedFix

When the buffer is modified, provide more specific information about what aspects of the buffer are modified. Handle this information in the widgets and update appropriately.
Fixing various memory leaks according to the Slicer memory management tutorial.
Fixes #18, Fixes #19: Using smart pointers to create/get nodes from the scene according to the suggestions from @ungi regarding commit @62581de20ee5b2853882f90b6a0ec1d8b347d26e.
Fixes #20: Use binary search algorithm to get/add transforms and messages in the transform buffer.
Attempting to fix according to transform node API changes.