Bump setup.py version for new release. (google#2473)

libClusterFuzz: Use utils.decode_to_unicode() instead of str.decode(). (

google#2452)

Add missing pytz dependency to setup.py. (google#2436)

Due to googleapis/python-ndb#707.

Update setup.py

Fix a pip dependency. (google#2434)

Remove an unnecessary dependency. (google#2394)

Prepare 2.5.0 release. (google#2393)

Bump reproduce tool version (google#2330)

Add 2.4.0 changelog entry. (google#2173)

Move timeout subtraction outside Engine.fuzz. (google#2108)

Currently it's not obvious at all to users of Engine.fuzz how long
fuzzing will go for when a max_time is passed.

Add Engine.fuzz_additional_processing_timeout so that the caller can
explicitly subtract the necessary processing time themselves if needed.

Remove engine_common.POSTPROCESSING_TIME. This was a holdout from the
launcher days. This is moved to the AFL launcher and can be removed
there as well once that's migrated to the Engine interface.