add menu for cubescript hooks

- add new hook "autoexec", executed right after autoexec.cfg
- properly report errors during hook execution
- new script to edit the contents of an alias in the console

DOCREF autoexec

source/src/main.cpp

@@ -1225,6 +1225,7 @@ int main(int argc, char **argv)
     exechook(HOOK_SP_MP, "afterinit", "");
     autostartscripts("");    // all remaining scripts
     execfile("config/autoexec.cfg");
+    exechook(HOOK_SP_MP, "autoexec", "");
     execute("addallfavcatmenus");  // exec here, to add all categories (including those defined in autoexec.cfg)
     initing = NOT_INITING;
     uniformtexres = !hirestextures;