Sorted map implementation with a left leaning red black tree. SMap is an interface for sorted maps and redblack implements it.
Remove the llrb tree, moving to redblack/ under smap/
Remove the Scanner interface from smap
Expose Interval and smap.Scan(Interval) -> Iterator
Remove Close() from smap.Iterator
Add Key() method to iterator, we need both keys and values
Move inOrder traversal to helper_test.go, only used in tests
Add more thorough tests on range scans and fix issues on open intervals.
Explain the semantics of Next() in regards to Value() and Key() in the Iterator interface
Merge pull request #2 from losmonos/llrb

sorted map implementation with a left leaning red black tree