Removed py2 lefotver, fix variable name.

Fix for removing files with space/parentheses.

Also, some further py2 cleanup.

Drop Python2 support.

Fix bad filenames for Python3.

In Python3, if there are filenames encoded with 8-bit encodings, there
might be an issues with converting them into unicode objects. This is a
workaround on this subject. Python2 is not affected.

Other than that, there was tests added to cover this case, appropriate
Makefile which automate creating venvs for both: Python 2 and 3, and
also there is a check against pep8 rules using flake8.

Added Python3 compatibility

Added new option for selecting adb executable

Added a functionality for accessing single directory

Added ability to use config file

Quote filenames, removing hardocded adb path