Refactor TreeView
Refactor: move kivy view code out
Add selection of target variable
First version that can classify things!
Threaded version
Add shared-memory multiprocess cross validation
Fix bug in shared numpy arrays
Async worker pool using condition variable

This version hangs when you terminate the worker pool.
Simplify multiprocessing training

Turns out the hang is inside Kivy and the actual method works fine.
Once that bug is resolved we can re-enable "stop classification"
Automatically select last variable on loading data

also update name on var chooser button and fix bug in GrizzlyModel.ready
Add gitignore