advanced test suit... failing tests have reasons eg. skew need 3 min_periods, kurt at least 4, etc. count produce NaN, where pandas.rolling produce 0.0, due to a pandas internal function call to .count if a indexer is given (freaky!)..

absolutly pandas conform tested - forward also works like pandas forward-hack, center is also tested

fixed constants detection. -there was the famous `ramp-up` error, because of the laggy implementation of pd.rolling ;)

Bump scipy from 1.5.2 to 1.5.3

See merge request !129

Bump urllib3 from 1.25.10 to 1.25.11

See merge request !132

Bump pygments from 2.7.1 to 2.7.2

See merge request !135

Bump zipp from 3.3.0 to 3.4.0

See merge request !136

Bump markdown from 3.3 to 3.3.3

See merge request !137

Bump pytest from 6.1.1 to 6.1.2

See merge request !141

Bump regex from 2020.10.11 to 2020.10.28

See merge request !142

Bump more-itertools from 8.5.0 to 8.6.0

See merge request !143

Bump pandas from 1.1.3 to 1.1.4

See merge request !144

Bump toml from 0.10.1 to 0.10.2

See merge request !145

Bump kiwisolver from 1.2.0 to 1.3.1

See merge request !146