Release 0.16.1

Fixes concurrency issues with the cache invalidation mechanism.

Release 0.15.2

Fix for ua-parser#132 on 0.15

Update uap-core to 0.16.0

Closes ua-parser#129

Release 0.15.1

- removed version bound from `setup_requires`, allows building from
  source when only PyYaml 6.0 is available (and downloading 5.4 is
  not), ua-parser#121, ua-parser#125
- added type assertion to parser lookup, to make the error clearer on
  type error, ua-parser#122, ua-parser#123
- fixed `setup.py build_regexes` and `setup.py build` for non-in-place
  builds, ua-parser#127

Deprecate js override bits

They were a feature for testing whose need was removed in
2015 (ua-parser/uap-core#58). They are *entirely* unnecessary, it is
possible a user somewhere is leveraging them for some reason.

So remove the override bits from the docstrings, and have them trigger
a `DeprecationWarning`.

Also:

- add tests that they do trigger
- remove support for them from the yaml testing functions
- update the pytest invocations to raise on all warnings
- while at it remove the apparently dead makePGTSComparisonYAML test
  utility method (?)
- and add pypy to the envlist

Note: `simplefilter` has to be updated to `"always"` for 2.7's dumb
      ass: the new tests triggers the same warning multiple times and
      of course `"default"` only yields them once.

Closes ua-parser#119