Added a way to directly specify the output directory independent of the action.

We will use this to support generating Xamarin Studio compatible projects with the VS action, while still invoking the Make action for native builds.

build/Helpers.lua

@@ -10,6 +10,10 @@ examplesdir = path.getabsolute("../examples");
 testsdir = path.getabsolute("../tests");
 
 builddir = path.getabsolute("./" .. action);
+if _ARGS[1] then
+    builddir = path.getabsolute("./" .. _ARGS[1]);
+end
+
 libdir = path.join(builddir, "lib", "%{cfg.buildcfg}_%{cfg.platform}");
 gendir = path.join(builddir, "gen");