Adaptation for Python 3 and solution for one task

All solutions has been modified to work with Python 3
Solution for 'Most Frequent Word' problem has been added
Anagram task solved

Solution for the 'Anagram' task has been added.
Revert "Anagram task solved"

This reverts commit a3804675147fc498881f9dfb3f73071535bf8de2.
Revert "Revert "Anagram task solved""

This reverts commit 128a159326c842996d614b80dc32cc719fd18767.