Need an explicit #exit to tell rake the exit status, not just returning the exit code

Author: eregon

lib/syntax_tree/rake/task.rb

@@ -61,7 +61,7 @@ def command
 
       def define_task
         desc "Runs `stree #{command}` over source files"
-        task(name) { run_task }
+        task(name) { exit run_task }
       end
 
       def run_task