Review fixes
Moved glob code from filesystem.dart to preferences.dart
Merge pull request #3707 from dart-lang/umop-preferences-editorconfig-glob

Create Glob class (for recursively matching paths to globs)
Resolved more conflicts
Merge branch 'umop-preferences-editorconfig-glob-complete' of https://github.com/dart-lang/chromedeveditor into umop-preferences-editorconfig