Improvements (#26)
* added logging of processed lines count
* added isort
* made passing settings by chain, updated naming
* fixed tests
* removed lines without effect from coverage
* added pytest, preparing for rewriting tests
* remade one testcase to pytest
* remade second testcase to pytest
* made structure to focus line working logic in Line class
* fix typo
* fixes
* updates
* more updates
* more tests
* tests updates
* fixed style
* md-translate 2.1.0
* test make common ci steps
* revert test, removed unused steps
