Move channel callback to a 2nd arg group

More idiomatic Scala.
Add DC TIE contactors

That move current from/to DC BAT BUS to/from DC BUS 1 & 2.
Consider only on-met actions for conditions

Currently, each `ConditionWatcher` object is associated with two
actions: one executed when the condition mets and another one executed
when the condition stops to met.

In some circumstances, several conditions are needed for the same
device. It could happen that when one of them is not met anymore it
could mean either other one is met or none of them are met. If a not-met
action is associated with each condition, that action could destroy
the work done by on-met handler of another condition.

This change fixes this by removing the not-met action of conditions. In
case of `Bus` class, this feature has been used to model conditions
determining what is the device that is energizing the bus.
Typo fixed
Fix a bug in condition evaluation

The tree of conditions was wrongly evaluated when there was more
than one node trying to evaluate the same condition. This may cause
that this node was notified by the event before its siblings, what
means an intermediate, inconsistent state that produces wrong
evaluations.

This change fixes the bug by moving the event notification to the
watcher and making it collect the event status (condition context) and
request the conditions to evaluate it.