Added new RxJS-BackPressure module defintion.

Fixed .gitignore to exclude rx.js from ignoring.

.gitignore

@@ -34,4 +34,7 @@ Properties
 *.iml
 *.js.map
 
+#rx.js
+!rx.js
+
 node_modules

rx.js/rx.backpressure.d.ts

@@ -0,0 +1,43 @@
+// Type definitions for RxJS-BackPressure v2.2.15
+// Project: http://rx.codeplex.com/
+// Definitions by: Igor Oleinikov <https://github.com/Igorbek>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+///<reference path="rx.d.ts" />
+
+declare module Rx {
+	export interface Observable<T> {
+		/**
+		* Pauses the underlying observable sequence based upon the observable sequence which yields true/false.
+		* @example
+		* var pauser = new Rx.Subject();
+		* var source = Rx.Observable.interval(100).pausable(pauser);
+		* @param pauser The observable sequence used to pause the underlying sequence.
+		* @returns The observable sequence which is paused based upon the pauser.
+		*/
+		pausable(pauser: Observable<boolean>): Observable<T>;
+
+		/**
+		* Pauses the underlying observable sequence based upon the observable sequence which yields true/false,
+		* and yields the values that were buffered while paused.
+		* @example
+		* var pauser = new Rx.Subject();
+		* var source = Rx.Observable.interval(100).pausableBuffered(pauser);
+		* @param pauser The observable sequence used to pause the underlying sequence.
+		* @returns The observable sequence which is paused based upon the pauser.
+		*/
+		pausableBuffered(pauser: Observable<boolean>): Observable<T>;
+
+		/**
+		* Attaches a controller to the observable sequence with the ability to queue.
+		* @example
+		* var source = Rx.Observable.interval(100).controlled();
+		* source.request(3); // Reads 3 values
+		*/
+		controlled(enableQueue?: boolean): ControlledObservable<T>;
+	}
+
+	export interface ControlledObservable<T> extends Observable<T> {
+		request(numberOfItems?: number): IDisposable;
+	}
+}