Back range_map._ordered_keys with a binary tree instead of list?

[mlenzen]

[mlenzen]

sorteddict (from blist) would probably be more efficient

[mlenzen]

Maybe add it as an option. A list is still the most efficient option for the first use case - an updating status that we want to check the history of.

[mlenzen]

A separate class seems like the best idea. Do we make RangeMap an abstract base class with two new classes inheriting or keep RangeMap as is and create a new subclass like TreeRangeMap.