WIP: Add mechanism for location prediction
API: Switch default linker to "auto" (numba when available)
ENH: Added ChannelPredict for channel flows.
WIP: Beginnings of demonstration notebook for predict.py
BUG: In ChannelPredict, interpolation is now based on bin centers.
DOC: Fixed typos in demonstration notebook for prediction
DOC: Improved linker docstrings and kwarg placement with regard to prediction.
PERF: Switch to KDTree as default neighbor_strategy; set fixed leaf_size
ENH: Prediction algorithm warns if insufficient data to make any prediction.
DOC: Add nkeim funding info to README
DOC: Updated prediction notebook to reflect KDTree default.
BUG: ChannelPredict now uses v = dx/dt
DOC: In linker docstrings, the first 'neighbor_strategy' is now 'KDTree', to reflect default.
BUG: Predict classes now issue proper warnings instead of raising exceptions.
CLN: Refactor predictors to make writing new ones easier; Add tests for ChannelPredict in y direction
ENH : auto-rebuild

Don't need to call `rebuild` on TreeFinder, now does it automatically
when `kdtree` is accessed if needed.
CLN: Remove redundant rebuilding of KDTree from link_iter()
PERF: prediction functions are now vectorized.
Merge pull request #75 from nkeim/add-predict

Add prediction capability