A field for storing periods of time - modeled in Python by timedelta. It
is stored in the native interval data type on PostgreSQL and as a bigint
of microseconds on other backends.
Also includes significant changes to the internals of time related maths
in expressions, including the removal of DateModifierNode.
Thanks to Tim and Josh in particular for reviews.
Made two-digit hours and minutes mandatory in tzinfo (the code used
to crash if a one-digit representation was provided).
Added standalone tests for django.utils.dateparse.
Tim Graham
Marc Tamlyn
Jon Dufresne
Richard Eames
Ray Ashman Jr
Aymeric Augustin
Adrian Holovaty