Fix null refrence when initializing DirectoryInfo from non share paths

[Jo0]

Changes

• Add BaseFileSystem test Fixture.
• Update TestFixture base class to better support testing of base filesystem and smbfilesystem
• Fix Object Null Reference when creating SMBDirectoryInfo with non share file path, by properly terminating the recursive call for _parent as per the System.IO.DirectoryInfo spec.
• Update directory object for SMBFileInfo(FileInfo,IFileSystem) to call SMBDirectoryInfoFactory.FromDirectoryName
• Remove trailing path on PathExtenstions.GetParentPath which was causing an extra call in SMBDirectoryInfo(string, FileInformation, IFileSystem, ISMBCredentialProvider, ISMBCredential).
• Properly determine and terminate _root in SMBDirectoryInfo when initializing by SMBDirectoryInfo(string, FileInformation, IFileSystem, ISMBCredentialProvider, ISMBCredential)
• Add NTStatus parameter in SMBFileSystemInformation constructor so that the conditional is actually utilized.
• Add share path implementation for SMBPath.GetPathRoot()
• Clean SMBDirectoryInfo constructor parameters so that it matches SMBFileInfo