EventAdmin shell: Removed the dependency to "utils"
Enhancements of the core shell service

- Added a IOHandler.write_line_no_feed() method:
  removes the trailing '\n' of an output line
  => Allows to use '\r' to rewrite the line

- Commands are looked in every namespace if none is indicated:

  - if the command exists in the default name space (e.g. stop): this command will be used
  - if the command exists in one name space only: this command will be used
  - if the command exists in different name spaces: an error message will be printed, with the name of
    those name spaces.