Fix .travis.yml for change to unittest build configs.

Author: jmdavis

.travis.yml

@@ -11,5 +11,5 @@ os:
     - osx
 
 script:
-    - dub test --build=doTests --compiler=${DC}
-    - dub test --build=doReleaseTests --compiler=${DC}
+    - dub test --build=unittest --compiler=${DC}
+    - dub test --build=unittest-release --compiler=${DC}