Another char-substitution list

[GoogleCodeExporter]

Add an option to use a simpler char-substitution list for directory and file 
names.

Use:
     A-Za-z0-9.-_

instead of:
     List<char> invalidList = new List<char>();
     invalidList.AddRange(Path.GetInvalidPathChars());
     invalidList.AddRange(Path.GetInvalidFileNameChars());

Original issue reported on code.google.com by [email protected] on 6 Jan 2013 at 11:00