Implementation of Segments filter class. Solve part of #110
Removing unnecessary Filter Exception Class. Solve part of #110
Implementation of Segments filter counting. Solve part of #110
Small dependency fix. Solve part of #110
Implementation of functions to count filtered data. Solve part of #110
Rename filter to sift. Solve part of #110

* filter is a Python built-in function. It shoudn't be used as a
  module name
Variable names improvement. Solve part of #110
Implementation of csv data exporting. Solve part of #110, #94 and #109