Merge branch 'release/v0.18.1' into develop
Moves options to driver.
Some more refactoring.
Migrates sources.py into separate module (additional sources should be placed in there).
Migrates logduration to LogTimer.
Moves drivers to dbnav.driver package. Simplifies drivers (extracts sources).
Simplifies driver code.
Version bump to v0.19.0.
Merge branch 'release/v0.19.0'