sanity check round 1, still needing block uniqueness checking and cycle checking (using a C++ set)
Merge branch 'master' of https://github.com/cpottamus/btree_lab

* 'master' of https://github.com/cpottamus/btree_lab:
  Debugging in progress
  Debugging in progress
  Debugging in progress; added print statements
  Debugging in progress; added print statements
  Debugging in progress; added print statements
  Debugging in progress; added print statements
  Debugging in progress; added print statements
  Debugging in progress (4); added print statements
  Debugging in progress (3); added print statements
  Debugging in progress (2)
  Debugging in progress (2)
  Debugging in progress