Advanced filtering added

[CezaryDanielNowak]

Possible filtering

// griddle.setFilter(filter):
filter = {
    columnName: "value",
    column2: "value2"
};
filter = [
    {columnName: "sth"},
    "filterAllColumns"
];
filter = /\S+@\S+\.\S+/; // regexp
filter = "works as before";

Some documentation is required, but I won't have time for doing this :-<

[CezaryDanielNowak]

ps. my editor unified tabs and spaces, I hope, this won't be a problem.

[kevinold]

@CezaryDanielNowak Thank you for your PR. In order to be approved and merged please:

1. submit .editorconfig in a separate PR
2. Provide tests and documentation patches for the proposed filtering

Thanks!