Changed scope of deferred variable in request function.

[tjmadsen]

Fixed issue #5 where deferred response was being overwritten when responding to simultaneous requests due to the fact that it's scope was broader than the request function.

[mattgoldspink]

Hi - this causes serious problems for us in our app. Could you please apply this pull-request to fix the issue?

Thanks

[chrisl8888]

this causes problems with testing as well. +1