Fix #266 - let FileSystem ctor figure out if an existing filesystem exists
Merge pull request #269 from humphd/issue266

Fix #266 - let FileSystem ctor figure out if an existing filesystem exists
Fix #270 and #276 - pathCheck should handle undefined paths and fix INAVL typo
Merge pull request #271 from gideonthomas/issue270

Fix #270 - pathCheck should handle undefined paths
v0.0.27