Fix: cleanup working dir after blender has exited

src/main/java/com/sheepit/client/os/OS.java

@@ -145,9 +145,18 @@ public abstract class OS {
 	 * @param proc Process to kill
 	 * @return true if proc wasn't null and was destroyed
 	 */
-	public boolean kill(Process proc) {
+	public boolean kill(Process proc) throws InterruptedException {
 		if (proc != null) {
 			proc.destroy();
+			
+			for (int i = 0; i <= 30; i++) {
+				if (proc.isAlive() == false) {
+					return true;
+				}
+				java.lang.Thread.sleep(100);
+			}
+			
+			proc.destroyForcibly();
 			return true;
 		}
 		return false;