reformat code
tmp commit
Merge remote-tracking branch 'origin/documentation-and-specification' into persistant-disk
refactoring
rename file system to file system data
remove dead code
rename file system manipulator to file system text manipulator
Merge remote-tracking branch 'origin/documentation-and-specification' into persistant-disk
created new class file system
replace file system data by options
tests
implemented ls tests
ls tests
refactoring
implemented more tests, refactoring
refactoring
refactoring
refactoring
implemented is directory
refactoring