issue #28 implementation

[Reckony]

No description provided.

[Reckony]

I was not sure if we want to pass all parameters that are optional in describe() method, so left only percentiles - seems most relevant, because list will contain only numerical data, so no need to include/exclude any type.
Description of the issue was very brief, so it is minimum implementation.

[SimonMolinsky]

Hi @Reckony

I've checked the changes, and thank you for the great tests for so simple function! Everything works as expected, but when I looked into the output statistics I saw that the column name is 0. Could you change it to summary? (It wasn't stated in the issue, but I think it could be nice to have this name instead of neutral zero :) )

[Reckony]

Requested changes done