cleanup Gruntfile.js and tasks.
add test/doget/case-02
add test/doget/case-02 and Gruntfile:expect_result task.
doget: add error handling.
clean up Gruntfile.js.
add test/doget/case-03 and modify dodget.js error handling.
Gruntfile: modify check-result task.
r2.v0.3.0