Since connection_proxy_connect is too long now, it's better to create
new functions (connection_https_proxy_connect,
connection_socks4_proxy_connect, and connection_socks5_proxy_connect) to
make connection_proxy_connect shorter.

Because we need to construct the URI using the TCPProxy configuration
but we don't have a standard URI scheme for haproxy yet, we decided to
not support TCPProxy in TOR_PT_PROXY now. There is no problem with
HTTPSProxy, Socks4Proxy, or Socks5Proxy because they all have standard
URI schemes.

Read the TCPProxy option and put in or_options_t.

TCPProxy is used for proxying all outgoing OR connections through some
proxy with the protocol specified in the option.

Obviously correct fixes to code that's already been reviewed.

These need to start with /**, not /*.

These are yet more that were not made with "/**"

There were a bunch of items where the doxygen comments were
formatted incorrectly (with /* instead of /**)

Previously some of the comments here used /*.

This makes out-of-tree doxygen builds work.

Closes ticket 32113.

Running doxygen with latex gave us all manner of unicode issues,
slowed down the "make doxygen" target by a lot, and added several
latex dependencies... all to produce a 4000-page reference manual
which is probably not what anybody wanted.

Closes ticket 32099.

I have left the settings at their old values, except when they
referred to nonexistent files.

Closes ticket 32110

Doxygen thinks that saying #foo is linking to a "foo" anchor
someplace.

Doxygen seems to interpret anything starting with \ as a command,
even when we don't mean it that way.