Added a check on unknown ESC command at compilation time (#438)

addons/escoria-core/game/core-scripts/esc/esc_compiler.gd

@@ -219,8 +219,9 @@ func _compile(lines: Array) -> Array:
 			returned.append(dialog_option)
 		elif command_regex.search(line):
 			var command = ESCCommand.new(line)
-			escoria.logger.trace("Line is the command %s" % command.name)
-			returned.append(command)
+			if command.is_valid():
+				escoria.logger.trace("Line is the command %s" % command.name)
+				returned.append(command)
 		else:
 			escoria.logger.report_errors(
 				"Invalid ESC line detected",