Test for nls line marker with 2 cases

Currently it tests only 'overriding' gutter icons
NlsLineMarker
Overrides marker works with include cycles

#WT-6 work 3h
Add messages and tests for them
Move getNlsName into NlsFileImpl
Fix tests and simplify algorithm

#WT-6 work 2h 30m
Implement overridden line marker

#WT-6 work 1h 45m
Remove unnecessary instanceof

#WT-6 fixed
Merge branch 'feature/wt6nlsgutter' into develop
Removed @author from sources

#WT-26 work 30m