This is needed for IOCP, since telling the IOCP backend about all
your CPUs is a good idea. It'll also come in handy with asn's
multithreaded crypto stuff, and for people who run servers without
reading the manual.
There are now four ways that CBT can be disabled:
1. Network-wide, with the cbtdisabled consensus param.
2. Via config, with "LearnCircuitBuildTimeout 0"
3. Via config, with "AuthoritativeDirectory 1"
4. Via a state file write failure.
All other bandwidthrate settings are restricted to INT32_MAX, but
this check was forgotten for PerConnBWRate and PerConnBWBurst. Also
update the manpage to reflect the fact that specifying a bandwidth
in terabytes does not make sense, because that value will be too
large.
This should be a very faithful conversion, preserving as much of the layout
of the old manpage as possible. This wasn't possible for the nt-service
and the DataDirectory/state parts. See a later commit for some small
cleanups.
Tiago Faria helped with the asciidoc conversion, big thanks!