Fix PrefixMode not being exported which caused runtime link errors.
Merge pull request #672 from SaberUK/master+rt-link-err

Fix PrefixMode not being exported which caused runtime link errors.
Use WriteNumeric() everywhere we send numerics and include the user's nick automatically
These two numerics are supposed to use SentText() as they can go to remote users...
Use gnutls_rnd instead of gcry_randomize on newer GnuTLS versions.

Also, fix a bug where eval() caused compile errors.
Merge pull request #685 from SaberUK/master+gnutls-rng

Use gnutls_rnd instead of gcry_randomize on newer GnuTLS versions.