Changes since 0.1:
* iset module was renamed to interval
* ISet class was renamed to IntervalSet
+ Added BaseIntervalSet and FrozenIntervalSet
+ Added the Smallest and Largest classes
+ Added the constant inf
* Moved ne, lt, le, gt, ge, incInterval, exInterval, and between to better-named
  class methods
* Moved all and empty to classmethods in BaseIntervalSet
- Removed eq
+ Added all as classmethod to Interval
- Removed Interval.__cmp__
+ Added Interval.comesBefore
* Renamed Interval.lbound to Interval.min
* Renamed Interval.linc to Interval.mininc
* Renamed Interval.ubound to Interval.max
* Renamed Interval.uinc to Interval.maxinc
+ Added __hash__ functions
+ Added BaseIntervalSet.__lt__
+ Added BaseIntervalSet.issubset
+ Added BaseIntervalSet.issuperset
+ Added BaseIntervalSet.union
+ Added BaseIntervalSet.intersection
+ Added BaseIntervalSet.difference
+ Added BaseIntervalSet.symmetric_difference
+ Added BaseIntervalSet.copy
+ Added IntervalSet.update
+ Added IntervalSet.intersection_update
+ Added IntervalSet.difference_update
+ Added IntervalSet.symmetric_difference_update
+ Added IntervalSet.discard
+ Added IntervalSet.pop
+ Added IntervalSet.__iter__
+ Added IntervalSet.clear
* Renamed IntervalSet.append to IntervalSet.add
+ Added IntervalSet.remove