We've removed all software that depends on or uses the TLS, NET, and
X.509 modules. This means TLS, NET, and X.509 are unused and can be
removed. Remove TLS, NET, and X.509.
Remove the copyright block from the Doxygen comments, to clean up the
detailed description in the generated Doxygen output. Also, add \file and
\brief tags to all headers in doxygen/input.