Accomodate whitespaces in original args to pass to wrapper

Hey, Doug. I made this change locally and thought I would submit a pull request. I was unable to use gdub when passing parameters containing a whitespace, e.g., `gw integTest -Ptags='foo bar'` invokes `gradlew` with the args `{"integTest", "-Ptags=foo", "bar"}` instead of `{"integTest", "-Ptags=foo bar"}`. This change seems to preserve the arguments.