Enable TLS by default, configure time.
Implement disable_hostname_check config option.

Patch by Sam Hartman.
Merge branch 'libradsec' of git.nordu.net:radsecproxy into libradsec

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Make sure that configure without --enable-tls works.

Also, --disable-tls, --enable-tls and --enable-tls=no.
Closes LIBRADSEC-2.
Disable/delete events in the timeout callback.

Without this, the sequence

  (1) send (successfully)
  (2) receive (timeout)
  (3) resend (successfully)

will have the read event from (2) trigger a read in (3) and the
response is lost.

Addresses LIBRADSEC-3.
Stop rs_request_send() from leaking RSE_TIMEOUT_CONN and RSE_TIMEOUT_IO.

If sending or receiving time out, pop the error off the stack before
continuing the loop. Push a new error, RS_TIMEOUT, before timing out
for real.

Addresses LIBRADSEC-3.
Avoid leaking memory when receiving a bad response.

A badly authenticated response message or one that didn't decode or
decrypt correctly was never freed. If caller didn't pass pkt_out, any
response was leaked as well.

As a bonus, the code is now readable too.
Add a debug printout when dropping an incoming response message.

Also, terminate another debug message with \n.
Clarify README.
Update documentation and configure.ac for libradsec-0.0.4.
Distribute new CHANGES file.
Bump version number.
Improve initialisation of OpenSSL PRNG.

Basic idea taken from Tor.
Remove unused code.
Don't use deprecated 'INCLUDES' variable in Makefile.am files.
Detect POSIX threads at configure time and use them for OpenSSL.
Update documentation with info on multithread protection.
Add PRNG improvements to CHANGES.
Ready for libradsec-0.0.5.
Move .gitignore to lib/ in preparation for moving lib to the root.