Localize client hello extension parsing in t1_lib.c

enabled instead of requiring an application to hard code a (possibly
inappropriate) parameter set and delve into EC internals we just
automatically use the preferred curve.

PR: 2778

add utility functions to t1_lib.c to check if EC certificates and parameters
are consistent with peer.

Submitted by: John Fitzgibbon <john_fitzgibbon@yahoo.com>

Time is always encoded as 4 bytes, not sizeof(Time).

PR: 2780

PR: 2775

PR: 2761
Submitted by: Corinna Vinschen

PR: 2776

Tidy some code up.

Don't allocate a structure to handle ECC extensions when it is used for
default values.

Make supported curves configurable.

Add ctrls to retrieve shared curves: not fully integrated with rest of
ECC code yet.

Fix memory leaks in 'goto err' cases.

workaround.

the old code came from SSLeay days before TLS was even supported.

distance between local labels.
PR: 2762

PR: 2435,2440