Reorganize ledStrip folder

- Remove 'blank' subfolder, move files up one folder to ledStrip
- Remove 'MUST_BE_RUN_AS_ROOT' files, it's explained in both READMEs
- Rename ledStrip files to indicate their ties to ledStrip.py, not blank.py
- Rename config.txt to ledStrip_config.txt
- Change example in config.txt to an image-based configuration