additional constants to improve upstream compatibility

* a few new error constants
*  WLED_O2_ATTR - ask the compiler for stronger optimization of a single function
*  WLED_O3_ATTR (WLEDMM) optimize even more

wled00/data/index.js

@@ -1976,6 +1976,9 @@ function readState(s,command=false)
 		case  3:
 			errstr = "Buffer locked!";
 			break;
+		case  7:
+			errstr = "No RAM for buffer!";
+			break;
 		case  8:
 			errstr = "Effect RAM depleted!";
 			break;