ENH: prototype data structure for managing a rolling window collection of panels for computation purposes
TST: make testing function more flexible
WIP: Convert batch_transform to use RollingPanel.
ENH: Adding minimal batch_transform code for benchmarking.
Resolved conflict.
TST: Split batchtransform tests into own file.
REF: Rewrite of batch_transform. Added unittest to test for newly appearing sids. Fixed logic bug where window was only full after window_length+1 events got passed.