[Typescript-Node] Add Support for useQuerystring Request Option #2905

[wing328]

cherry-pick based on #2905

credit: @pixelshaded

[wing328]

Test cases passed

> @swagger/[email protected] build /Users/williamcheng/Code/cherrypick/swagger-codegen/samples/client/petstore/typescript-node/npm
> tsc

Created pet with ID 18291
Updated pet using POST body
Updated pet using POST form
Uploaded image
Got pet by ID: {"id":18291,"name":"TypeScriptDoggie","photoUrls":["http://url1","http://url2"],"tags":[{"id":18291,"name":"TS tag 1"}],"status":"pending"}
Deleted pet
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:08 min
[INFO] Finished at: 2016-05-29T11:52:35+08:00
[INFO] Final Memory: 11M/245M
[INFO] ------------------------------------------------------------------------

[pixelshaded]

The only thing here that might not have been necessary was replacing the finally() with a then() in the client.ts / test client. I was thrown off by the alias for bluebird being Promise. Native promises don't support finally (aka promises from the node/corejs typings), but bluebird does. Finally should have been ok to leave, but I can't remember if I resolved this or not in my PR. I originally removed it because of typing / build issues.