Rename ApplicationDelegate to SDKApplicationDelegate to avoid name clashes.

[nlutsenko]

Preventing name clashes, as ApplicationDelegate is likely to exist in the app module.

Closes #35

[1dotd4]

Wait why not FBApplicationDelegate?
SDKApplicationDelegate is too ambiguous

[nlutsenko]

We already have SDKSettings and SDKVersion.
Biggest reason - Swifty names :)
The full name for SDKApplicationDelegate is FacebookCore.SDKApplicationDelegate, and since FacebookCore.FBApplicationDelegate would be too much of FB/Facebook in the name - we stick to SDKApplicationDelegate/SDKSettings.

[nlutsenko]

This is a good point, and we might want to revisit this naming later, while we are still in beta.

[richardjrossiii]

Agree with returning to naming in the future. If we had proper submodules, I would say we have Facebook.ApplicationDelegate, with Facebook.Login and Facebook.Share as other modules. But alas, that's currently not possible.