Initialise context before using it.
(cherry picked from commit a4947e4e064d2d5bb622ac64cf13edc4a46ed196)
Sync error codes with 1.0.2-stable
Enable PSK in FIPS mode.

Enable PSK ciphersuites with AES or DES3 in FIPS mode.
Experimental workaround TLS filler (WTF) extension.

Based on a suggested workaround for the "TLS hang bug" (see FAQ and PR#2771):
if the TLS Client Hello record length value would otherwise be > 255 and less
that 512 pad with a dummy extension containing zeroes so it is at least 512.

To enable it use an unused extension number (for example 0x4242) using
e.g. -DTLSEXT_TYPE_wtf=0x4242

WARNING: EXPERIMENTAL, SUBJECT TO CHANGE.