Moved docstring to __init__

in prog: adding more tests

added path to tests/assets
added test cases for regex splits

added xpath building function, is backwards compatible with previous releases
local merge with optimizations

commiting algorithm progress
eatiht_v2.py is script

added class structure (eatiht_trees.py) to represent state space elements
small edits in etv2.py: corrected import statement and took out commented out xpath
removed unused variables within extract functions