Creates delegation of DCIntrospect and update the demo.

[lxcid]

Allows user to extends useful functionality, like keyboard inputs, for their own use cases.
As the project is iOS 4 compatible, delegate property is set as assign, which requires the user to nil the delegate upon deallocation.
It would be better if we can make use of the weak property attribute instead which release the user the responsibility of setting the delegate to nil.

[jklp]

Hi, thanks for the pull request though unfortunately it looks like DCIntrospect is no longer maintained. Good news though, myself and @Logicreative have decided to revive DCIntrospect, and created a fork at https://github.com/logicreative/DCIntrospect-ARC to hopefully merge all pull requests and forks back into a single repo.

If you don't mind sending your pull request to the DCIntrospect-ARC repo, we'll try and merge it as quickly as possible. We're also going to be more active with the CocoaPods package manager, so we'll update the latest CocoaPod's podspect once all changes have been merged.

Thanks
Jerrold