Multiple Bridge lines can point to the same one ClientTransportPlugin
line, and we can have multiple ClientTransportPlugin lines in our
configuration file that don't match with a bridge. We also issue a
warning when we have a Bridge line with a pluggable transport but we
can't match it to a ClientTransportPlugin line.

* Tweaked doxygen comments.
* Changed returns of get_proxy_addrport().
* Ran make check-spaces.
* Various small code tweaks.

* Renamed transport_info_t to transport_t.
* Introduced transport_get_by_name().
* Killed match_bridges_with_transports().
  We currently *don't* detect whether any bridges miss their transports,
  of if any transports miss their bridges.
* Various code and aesthetic tweaks and English language changes.

It creates some helper functions that return the proxy type, proxy addr/port, etc.

Not included in the previous commit, because the implementation is
ugly; I see no other way of doing this though.

* Improved function documentation.
* Renamed find_bridge_transport_by_addrport() to
  find_transport_by_bridge_addrport().
* Sanitized log severities we use.
* Ran check-spaces.

Before, it wasn't really obvious if one meant hours:minutes or
minutes:seconds etc.

When we set a networkstatus in the non-preferred flavor, we'd check
the time in the current_consensus.  But that might have been NULL,
which could produce a crash as seen in bug 3361.

George Kadianakis notes that if you give crypto_rand_int() a value
above INT_MAX, it can return a negative number, which is not what
the documentation would imply.

The simple solution is to assert that the input is in [1,INT_MAX+1].
If in the future we need a random-value function that can return
values up to UINT_MAX, we can add one.

Fixes bug 3306; bugfix on 0.2.2pre14.

so that parse_log_domain() doesn't fail.

When we added the check for key size, we required that the keys be
128 bytes.  But RSA_size (which defers to BN_num_bytes) will return
128 for keys of length 1017..1024.  This patch adds a new
crypto_pk_num_bits() that returns the actual number of significant
bits in the modulus, and uses that to enforce key sizes.

Also, credit the original bug3318 in the changes file.