entrpoint now uses exec to call the entrypoint command thus not spawing a subshell
updated uci shell code and added /root/shell so to avoid constant warning about it missing.
add /opt/bin to path in dockerfile
refactored: Dockefile template
refactor: example and move src/ there a simple example
new: distros.csv holds table of valid distros, their images and install/update commands
refactor: various fixes and adjustment in response to above
refactor: help vastly improved and updated
David Kebler