Changes

fixes #2854
- PragmaSetting>>chooseFileDirectory returned string path before this
fix instead of file reference instance. This caused problem, when
FileLocator>>resolve tried to resolve local directory and file reference
was expected. 
- fix will prevent from entering invalid directory directly by typing,
so only valid directory setting is accepted (SystemResolver class>>
userLocalDirectory:)
- test was added

Fixing SystemResolverTest>>tearDown - super tearDown should be last
statement