Added initial console commands for plugins

fixed crash in plugin destructor
fixed compilation not being freed causing a crash
fixed small issues in plugin system
fixed plugin iterator not being reseted when freed and not being initialized it's current pointer.
fixed a bug where insertion of a prefixed string would not check whether a value could be set.

--HG--
extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%40221

core/sm_trie.cpp

@@ -603,6 +603,12 @@ bool sm_trie_insert(Trie *trie, const char *key, void *value)
 				/* Do an initial browsing to make sure they're not the same string */
 				if (strcmp(keyptr, term) == 0)
 				{
+					if (!node->valset)
+					{
+						node->valset = true;
+						node->value = value;
+						return true;
+					}
 					/* Same string.  We can't insert. */
 					return false;
 				}