Merge pull request #19 from yamada-h/gui-dev

auto topology creation and modification for test
jsPlumb: create endpoint per port_no.
javascript: code cleanup
add check for delLink
update topology test

- mininet操作を分離
- フローの追加・変更・削除を追加
Merge pull request #20 from yuta-hamada/gui-dev

javascript: update
remove unnecessary import
Merge pull request #21 from yuta-hamada/gui-test

update topology test