….vsi file was causing exception when parsing .ets file. Added logic to dynamically associate .efs files with .vsi file metadata.

…o associated metadata block in the .vsi file, its contents are omitted from the series list, and the file is treated the same way as the blob_*.meta files, which is to say, their names are included in the 'extraFiles' list, and they are otherwise ignored.

… given 'pyramid' metadata struct is not associated with more than one ETS file. This change is to handle the case where the image sizes of multiple ETS files are the same or nearly the same as a single 'pyramid' metadata struct, resulting in an erroneous associations that cause the program to crash.

…he filemap.