properly escape invocation arguments

tests/RunTravis.hx

@@ -337,13 +337,13 @@ class RunTravis {
 				Sys.setCwd("../sys");
 				runCommand("haxe", ["compile-neko.hxml"]);
 				Sys.setCwd("bin/neko");
-				runCommand("neko", ["sys.n", "foo", "12", "a b c\\"]);
+				runCommand("neko", ["sys.n", "foo", "12", "a b c\\\\"]);
 			case "python-sys":
 				getPythonDependencies();
 				Sys.setCwd("../sys");
 				runCommand("haxe", ["compile-python.hxml"]);
 				Sys.setCwd("bin/python");
-				runCommand("python3", ["sys.py", "foo", "12", "a b c\\"]);
+				runCommand("python3", ["sys.py", "foo", "12", "a b c\\\\"]);
 			case "openfl-samples":
 				getOpenFLDependencies(unitDir);