[lua] add vr.error(...) (same as vr.print())

Change-Id: I2a88925ccc206db08818c8e4810b51ab2a97a49c

Author: stbuehler

doc/core_lua.xml

@@ -235,7 +235,7 @@
 
 				Methods:
 
-				* `print(...)`: print parameters via lua `tostring` method as ERROR in Virtual Request context
+				* `error(...)` and `print(...)`: print parameters via lua `tostring` method as ERROR in Virtual Request context
 				* `warning(...)`: print parameters via lua `tostring` method as WARNING in Virtual Request context
 				* `info(...)`: print parameters via lua `tostring` method as INFO in Virtual Request context
 				* `debug(...)`: print parameters via lua `tostring` method as DEBUG in Virtual Request context

src/main/virtualrequest_lua.c

@@ -319,6 +319,7 @@ static const luaL_Reg vrequest_mt[] = {
 	{ "__newindex", lua_vrequest_newindex },
 
 	{ "print", lua_vrequest_error },
+	{ "error", lua_vrequest_error },
 	{ "warning", lua_vrequest_warning },
 	{ "info", lua_vrequest_info },
 	{ "debug", lua_vrequest_debug },