* usr/bin/byobu-disable-prompt, usr/bin/byobu-enable-prompt,
  usr/share/byobu/profiles/bashrc,
  usr/share/byobu/profiles/Makefile.am,
  usr/share/byobu/profiles/ps1.sh:
  - use a common bashrc file
* usr/share/byobu/profiles/bashrc:
  - allow override via a $DISTRO env variable
* usr/bin/byobu-disable-prompt, usr/bin/byobu-enable-prompt,
  usr/share/byobu/profiles/bashrc:
  - don't put profile reloads in the bash history
  - use a ~/.byobu/prompt file as a redirect, and to enable
    end user customizations
  - fix a bash error
* usr/bin/byobu-enable-prompt, usr/bin/byobu-janitor:
  - enable the new byobu colored prompt by default, on new logins
* usr/bin/byobu-janitor:
  - enable users to remove the line from their ~/.bashrc