Removed try/catch requirement

* The try/catch block was causing an exception when the named segue did
not exist in the storyboard
* The custom segue did not have a custom class defined which is not
allowed
* revised the implementation to instantiate the view controller by
identifier without segues
* updated docs and added a new example of a storyboard

Try setting an exception breakpoint on the current code to see that it can through an exception. I'd like to avoid that happening and give the developer a way to override behavior. This update allows for inheriting the base class and overriding 3 methods.

![breakpoint on exceptions](https://f.cloud.github.com/assets/277419/2507630/537e5c4a-b3c1-11e3-84f3-4318b393e3e5.png)