Starting to add cursor state stuff.

- Stateless tree traversal sucks.
- typedef'd the ol_stack struct, finally
- Added ol_subtree_maximum back in because we might need it
Added cursor files.
REFACTOR INCOMING
Trivial commit to thunk Richelieu.
Fixes #72.

Removed the erlang requirements for liboleg.
Attempting co-routine traversal of the tree with setjmp.

Insanity calls for hardened tools, like my iron heart.
Removed the setjmp shit.
The thing I was looking for is caled the 'in-order successor' algorithm.
Cursor rewrite works.
Fix clang bug.
Fix the inline shit because clang.
Update cursor.h

Oxford comma. Learn it.
Merge pull request #79 from infoforcefeed/feature/Cursor-Rewrite

Feature/cursor rewrite