[TravisCI] haxelib dev heaps . (#341)

.travis.yml

@@ -10,10 +10,15 @@ haxe:
 matrix:
   allow_failures:
     - haxe: development
-    
-script:
+
+install:
   - yes | haxelib install all
-  - haxe all.hxml
-  - cd samples
+  - pushd samples
   - yes | haxelib install all
+  - popd
+  - haxelib dev heaps .
+  - haxelib list
+
+script:
   - haxe all.hxml
+  - haxe --cwd samples all.hxml