- fixes and feedback from @gfanti and @amiller
- addresses #1049
- minor refactoring
- two global child stems with fixed mapping between parent and
child stem
- allow child stems which don't support dandelion
- only allow outbound connections to be stems
- adjust stems if opening/closing outbound connections (should
allow partial dandelion functionality when not enough outbound
connections are available instead of breaking)
- most of the stuff is done so it partially works
- disabled pollers other than select (debugging necessary)
- can switch in the settings, section network, option asyncore (defaults
to False)