Feature/landing screen

This PR will lay more foundation on our network classes and co.

## Classes

* ```Client.swift``` : This class is responsible as an interface layer with controller. Frequently used methods such as ```find```, ```findAll``` are provided. (Many more to come, such as ```create```, ```update```
* ```ClientConfiguration.swift``` : This class hosts the configuration of ```Client``` itself.
* ```ClientRouter.swift``` : This class is responsible for finding API endpoint router for entity as index, and as list. Index is single entity, List is for multiple entities, it is pretty much the same as SELECT with ID and SELECT all.
* ```ClientResourceMapper.swift``` : This class is for mapping JSON payload into Swift object, it can be any implementation that support as such workhorse.
* ```ClientResourceNamer.swift``` : This class is to convert between, class name and API path endpoint. Default implementation is name of Swift class itself as ```lowercaseString```

## Usage

At client class which can be anywhere, popular candidate might be viewController

``` Swift
let client = Client(config: AMClientConfiguration.sharedInstance)

//find movie by ID
client.find(Movie.self, id: "1", pathArguments: nil) { (request, response, movie, error) -> Void in
    if let m = movie as? Movie {
        NSLog("%@", m)
    }
    NSLog("%@", response!)
}

//find movie by category
```
`as?` can check is it nil or not, and this line is not necessary