Refactor for latest environment

I want to use this in latest rubymotion environment (ver 2.2) with [clearsightstudio/ProMotion](https://github.com/clearsightstudio/ProMotion), but, I have seen a trouble.

ProMotion make us use PM::Delegate class instead of AppDelegate class.
(e.g. https://github.com/jamonholmgren/promotion-demo/blob/master/app/app_delegate.rb)
So, RubyMotion will raise superclass mismatch when using ProMotion with motion-stump,
because motion-stump builds simple default [app_delegate.rb](https://github.com/siuying/motion-stump/blob/master/lib/stump/app_delegate.rb) which don't inherit other class,
but ProMotion's app_delegate.rb use AppDelgate class which inherit PM::Delegate class.

I make some refactor commit for this repository.

1. refactor for latest rubymotion environment
  1. remove app_delegate.rb to build when using by gem user.
  2. fit to latest build procedure(don't override spec_files and override spec_core_files. https://github.com/HipByte/RubyMotion/blob/master/lib/motion/project/config.rb#L249) 
2. clean repository
  1. replace Rakefile's line feed code from CR to LF.
  2. update .gitignore for developer