released 3.1.20
use RUSAGE_THREAD when available
reduced the TLS version requirements for all ciphersuites that are not GCM.
tolerate servers that included the SUPPORTED ECC extension.

This is an extension that is defined to be sent by the client but there
are servers that include it as well. Most other implementations tolerate
this behavior so we do.

Conflicts:
	lib/ext/ecc.c
doc update
When two initial keywords are specified then treat the second as having the '+' modifier.

This will handle SECURE256:SECURE128 the same way as SECURE256:+SECURE128.
doc update
When setting multiple initial keywords in a priority string, the security level set is the one of the lowest security.

Conflicts:
	lib/gnutls_priority.c