Update node.d.ts

headers return an object

http://nodejs.org/api/http.html#http_message_headers
Added additional definitions to Valerie

Added ModelValidation types
Added more static valerie namespace definitions
rx.js renamed to rx.
Added few helpers functions.
Removed rx files before merging.
Merge remote-tracking branch 'rx/master' into RxJS
Added few helpers functions.
Merge branch 'master' of https://github.com/Igorbek/rx.d.ts into RxJS
Added ObservableStatic.from definition.
Removed scheduler parameter from fromCallback and fromNodeCallback.
Exchanged parameters scheduler and context in ObservableStatic.start.
Exchanged parameters scheduler and context in ObservableStatic.toAsync.
Merge branch 'master' of https://github.com/Igorbek/rx.d.ts into RxJS
Added return type annotation in ObservableStatic.from.
Merge branch 'master' of https://github.com/Igorbek/rx.d.ts into RxJS
Fixed rx.async-tests.ts.
Merge branch 'master' of https://github.com/Igorbek/rx.d.ts into RxJS
Merge remote-tracking branch 'upstream/master'
Knockout: amended components.register to overloads supported by 3.2

KO Version 3.2 added components. The .register method in the current
code is incorrect and does not support the correct overloads permitted.