Created a FileIterator.files() method that return files only.
Removed the duplicated method definitions from FileInfo, that were
already defined in FileIterator.
Renamed FileIterator.getFilesAndDirs() to FileIterator.getFiles(), since
none of the uses of that method presently need access to nested
directories.
Merge pull request #537 from BladeRunnerJS/file-iterator-improvements

File iterator improvements