assertions.like: Fixed typo in `not_to_be_like()`
core: Generated `not_*` assertions no longer add a (useless) docstring
Added package docstring
Added preggy.__meta__
Use preggy.__meta__ in {__init__,setup}.py
Added __main__ (prints quick assertions reference)
__meta__:__date__: Remove leading zeroes (does py3 hate them?)
Merge pull request #14 from Zearin/v0.9.0/9_assertion_cheatsheet

Close #9: Print assertion cheatsheet with `python -m preggy`