Added support to itemGen-scaled.sh for source content with dots in the filename (H.264_720p_AC3_210s.ts again)

odid doesn't allow for dots in a resource basename. Updated the itemGen-scaled.sh
 script to convert dots to underscores if/when present.

Tested with all content files currently in convert-dlna-scaled-helper.sh. Rygel/odid
 no longer reports any issues with empty extensions, etc.