[BUG #7325] forked out Watcher() class from watch() method

- a class only concerned with the files and directories to watch
- no timing, no actions
[BUG #7325] include rootpath in the result list

- important if checking a single file instead of a directory tree
[BUG #7325] add support for live reload as 'source-server-reload' job

- using the source-server to also monitor the script file
- and a client-side script that polls for updated versions
  (injected by the web server)
[BUG #7325] add 'source-server-reload' job to skeletons and manual