Fix issue #222 with matches_filters method

[Antelox]

Issue reported here: #222

I have just refactored the code in order to keep the matching logic the same and at the same time to take into account the use case that is causing the wrong matching when filters have more negated fields that matches the headers values.

I have also updated the unittest related to the task filters with negation.

In [1]: from karton.core import Task
In [2]: Task({
   ...:     "type": "sample",
   ...:     "kind": "runnable",
   ...:     "platform": "win32",
   ...:     "extension": "msix"
   ...: }).matches_filters([
   ...:         {"type": "sample", "kind": "runnable", "platform": "win*", "extension": "!msi*"},
   ...:         {"type": "sample", "kind": "runnable", "platform": "win*", "extension": "!lnk"},
   ...:         {"type": "sample", "kind": "document", "platform": "win*"}
   ...:     ])
   ...: 
Out[2]: False

$ python -m unittest discover tests/
.............
----------------------------------------------------------------------
Ran 13 tests in 0.040s

OK

[psrok1]

Looks good. I was thinking about changing matched list of bools into single bool with &= operator but impact on performance is negligible for such short lists.