Revert "Remove vestiges of logging"

Re-enable the logging stuff on the logging_enabled branch.

This reverts commit 2a09ccbd63.

include/olm/olm.hh

@@ -415,6 +415,13 @@ size_t olm_ed25519_verify(
     void * signature, size_t signature_length
 );
 
+/**
+ * Set the log level. By default, 1, which logs only FATAL messages.
+ */
+void olm_set_log_level(
+    unsigned int level
+);
+
 #ifdef __cplusplus
 }
 #endif

javascript/olm_post.js

@@ -382,4 +382,6 @@ Utility.prototype['ed25519_verify'] = restore_stack(function(
 olm_exports["Account"] = Account;
 olm_exports["Session"] = Session;
 olm_exports["Utility"] = Utility;
+
+olm_exports['set_log_level'] = Module['_olm_set_log_level'];
 }();