Add playground page and README

Author: freak4pc

Playground/RxSwiftExtPlayground.playground/Pages/Index.xcplaygroundpage/Contents.swift

@@ -44,6 +44,7 @@
  - [ofType()](ofType) operator, filters the elements of an observable sequence, if that is an instance of the supplied type.
  - [toSortedArray()](mapMany) operator, converts an Observable into another Observable that emits the whole sequence as a single array sorted using the provided closure and then terminates.
  - [count(predicate)](count) operator, counts the number of items emitted by an Observable. If predicate exists, then counts the number of items satisfying it.
+ - [partition](partition) operator, partition a stream into two separate streams of elements that match, and don't match, the provided predicate.
  - **UIViewPropertyAnimator** [animate()](UIViewPropertyAnimator.animate) operator, returns a Completable that completes as soon as the animation ends.
  - **UIViewPropertyAnimator** [fractionComplete](UIViewPropertyAnimator.fractionComplete) binder, provides a reactive way to bind to `UIViewPropertyAnimator.fractionComplete`.
 */

Playground/RxSwiftExtPlayground.playground/Pages/partition.xcplaygroundpage/Contents.swift

@@ -0,0 +1,25 @@
+/*:
+ > # IMPORTANT: To use `RxSwiftExtPlayground.playground`, please:
+ 
+ 1. Make sure you have [Carthage](https://github.com/Carthage/Carthage) installed
+ 1. Fetch Carthage dependencies from shell: `carthage bootstrap --platform ios`
+ 1. Build scheme `RxSwiftExtPlayground` scheme for a simulator target
+ 1. Choose `View > Show Debug Area`
+ */
+
+//: [Previous](@previous)
+
+import RxSwift
+import RxSwiftExt
+
+example("partition") {
+    let numbers = Observable
+        .of(1, 2, 3, 5, 8, 13, 18, 21, 23)
+
+    let (evens, odds) = numbers.partition { $0 % 2 == 0 }
+
+    _ = evens.debug("even").subscribe()
+    _ = odds.debug("odds").subscribe()
+}
+//: [Next](@next)
+

Readme.md

@@ -81,6 +81,7 @@ These operators are much like the RxSwift & RxCocoa core operators, but provide
 * [Observable.zip(with:)](#zipwith)
 * [withUnretained](#withunretained)
 * [count](#count)
+* [partition](#partition)
 
 There are two more available operators for `materialize()`'d sequences:
 
@@ -598,6 +599,20 @@ next(3)
 completed
 ```
 
+#### partition
+
+Partition a stream into two separate streams of elements that match, and don't match, the provided predicate.
+
+```swift
+let numbers = Observable
+        .of(1, 2, 3, 4, 5, 6)
+
+    let (evens, odds) = numbers.partition { $0 % 2 == 0 }
+
+    _ = evens.debug("even").subscribe() // emits 2, 4, 6
+    _ = odds.debug("odds").subscribe() // emits 1, 3, 5
+```
+
 Reactive Extensions details
 ===========