Agent howtos manually call reactor.run/reactor.stop

[habnabit]

All of the code snippets in the Agent howto would be simplified by use of t.i.task.react instead of calling reactor.run() and reactor.stop() in a deferred callback. This would also show the modern idiom for spinning up a reactor for only one task.

[exarkun]

While addressing this issue, please consider that simply switching to react may not actually simplify the examples. Instead, it may make them more complex by introducing a new concept which must be understood before the examples can be understood.