Document FuzzyInteger.step
Document custom manager method recipe (Closes #119).
Fix bug in LazyStub.__getattr__

When run with optimizations turned on, the assert statement
is not executed. This results in incorrect behaviour.
Update ChangeLog
Merge branch 'maint/2.3.x'

Conflicts:
	docs/changelog.rst
Added "prevent_signals" decorator/context manager
Improve mute_signals (Closes #122).
Add doc for factory.django.mute_signals.
Update requirements
Fix log_pprint (Closes #123).
Fix mute_signals' decorator.
Fix log_pprint (Closes #123).
Update ChangeLog.
Merge branch 'maint/2.3.x'
Fix log_pprint for *args (Closes #127).
Fix log_pprint for *args (Closes #127).
Merge branch 'maint/2.3.x'
fuzzy: Add FuzzyFloat (Closes #124).

As suggested by @savingschampion
Release v2.3.1
Merge branch 'maint/2.3.x'