Feature req: circuit controls - number and rotation

[grarpamp]

Hi.
Tor seems to rotate perfectly good circuits out of production on
more or less regular intervals. For any number of good reasons of
course. And it likewise aims to have a certain amount open all the
time. It would be handy to have controller settings to:

- halt/continue rotation
- set the number of open circuits

This would be particularly useful when debugging connection issues.


Oh hey, thanks for all the work on the newly released stable branch.
Love the transparent proxy stuff.