Return 1 when setting ECDH auto mode.
Make no-ec compilation work.
Don't run ECDH CMS tests if EC disabled.
Add documentation.

Preliminary documentation for chain and verify stores and certificate chain
setting functions.
Typo: don't call RAND_cleanup during app startup.
(cherry picked from commit 90e7f983b573c3f3c722a02db4491a1b1cd87e8c)