Using raw integers forces us to select a pre-defined
start and end ranges for the timeline. Since we want
to reuse this data structure on GcalTimeline, make it
a bit more useful.
In order to correctly implement the week grid, we must
have a fast and optimized data structure to handle date
intervals.
This commit introduces, then, GcalRangeTree. The range tree
is an augmented AVL tree designed to handle intervals (i.e.
ranges) rather than single-dimensional keys.
It is a very good struct since common operations like insert
and removal are O(log n). It also is optimized for the ranges
we work on, so the nodes only take up the absolutely minimum
space required.
Georges Basile Stavracas Neto