Quick/Quick — pull request #175 by modocache (2014-10-28 06:32:36+00:00)
Title: Provide a hook to configure Quick

Merge after #174.

This allows Quick to be configured using the following syntax:

```swift
class MyProjectConfiguration: QuickConfiguration {
override class func configure(configuration: Configuration) {
configuration.beforeEach { /* ...this is executed before each example, globally. */ }
}
}
```

This set of commits removes `QuickSharedExampleGroups`. Instead, users can define shared examples within the configuration class:

```swift
class SharedExamplesConfiguration: QuickConfiguration {
override class func configure(configuration: Configuration) {
sharedExamples("my shared examples") { /* ... */ }
}
}
```

Fixes #163. Supports #152.