[OTFC][daemon] Set keys via http server

Summary: With this diff we can set the keys via http server.

Test Plan:
  $ rm ./daemon; go build github.com/gow/otfc/daemon && ./daemon 1,2>/dev/null &

  $ curl  http://localhost:8088/get?key=123\&value="ssf     sfs"
  {"Status":"error","Err":{"ErrNo":2002,"ErrInfo":"key [123]"}}

  $ curl  http://localhost:8088/set?key=123\&value="ssf     sfs"
  {"Status":"OK","Key":"123","Value":"ssf\u0009sfs"}

  $ curl  http://localhost:8088/get?key=123\&value="ssf     sfs"
  {"Status":"OK","Key":"123","Value":"c3NmCXNmcw=="}

  $ base64 -d
  c3NmCXNmcw==
  ssf sfs

Reviewers: tommy.testy

Reviewed By: tommy.testy

Differential Revision: http://dev.chetan.io/D39