PredictedCircsRelevanceTime: limit how long we predict a port will be used

By default, after you've made a connection to port XYZ, we assume
you might still want to have an exit ready to connect to XYZ for one
hour. This patch lets you lower that interval.

Implements ticket 91
Added Documentation for PredictedCircsRelevanceTime config file argument.
Added max value to PredictedCircsRelevanceTime.
More correctly documented PredictedCircsRelevanceTime in tor.1.txt
Fixed spacing.
Lower the maximum for PrecictedCircsRelevanceTime to one hour
Fix wide lines.
Merge branch 'ticket9176_squashed'

Conflicts:
	doc/tor.1.txt
Rename PredictedCircsRelevanceTime->PredictedPortsRelevanceTime

All circuits are predictive; it's the ports that are expiring here.
Fix whitespace errors, all of them mine.