bug fixes and tree schema in v1.2

refactored into several files, fixed bugs associated with
"nodeById" being in the v1.2 schema (not "nodesById"),
schema for nodes, edges, leafs, internal. Only validating
trees in v1.2
more thorough root checking
ottid checking in 0.0 not in 1.2 yet
checking ottid in v1.2
testing for dup ott finished
warning message formatting
unchecked tests. Expected output not verified!
bug fixes and, still largely untested, tests
cleaning up tests
better checking when isLeaf is False
added tests for incorrect source or target attr of edges
bailing out faster for a lot of error types
Bailing out earlier on errors

Logs cause of first error to _LOG. Warnings and errors
get cropped in the test files.
merged validator and deleted search_for_study_dirs