Add a way to combine two IntervalDict's

[AlexandreDecan]

(From #13, @msarrel):

One feature that would be useful for me is to define addition, subtraction, etc. for IntervalDict. That is if we have two IntervalDicts:

[1, 3] | [5, 7] = 1
and
[2, 4] | [6, 8] = 2

Their sum would be a single Interval Dict with three entries:

[1, 2) | [5, 6) = 1
[2, 3) | [6, 7) = 3
[3, 4] | [7, 8] = 2

The idea would be to provide a d.combine(other_d, func) that takes values from d and other_d and applies func on them for every intersecting pair of intervals (as in the example, letting the values of the non-intersecting parts of these intervals as-is).

[AlexandreDecan]

Implemented in 27bc736, will be part of next release (1.10.0). Can already be used with pip install from git.

[AlexandreDecan]

Release 1.10.0 is now available on PyPI.