Implemented chat logging options for OTR messages

on - Log OTR messages as plaintext
off - Do not log OTR messages
redact - Log, but replace the text with '[redacted]'

Defaults to redact

src/otr.h

@@ -42,7 +42,8 @@ char * otr_get_my_fingerprint(void);
 char * otr_get_their_fingerprint(const char * const recipient);
 
 char * otr_encrypt_message(const char * const to, const char * const message);
-char * otr_decrypt_message(const char * const from, const char * const message);
+char * otr_decrypt_message(const char * const from, const char * const message,
+    gboolean *was_decrypted);
 
 void otr_free_message(char *message);