* Added ability to set options for layouts. NSLayoutFormatDirectionLeadi...

This branch adds to new features:

* horizontal/vertical methods accept extra options argument. As in cocoa the default option is NSLayoutFormatDirectionLeadingToTrailing

* Layout object can accept delegate call in initialiser, then subviews can be passed as an array of symbols pointing to methods or instance variables in the delegate. examples:

```ruby
@from = UILabel.new
@subject = UILabel.new

Motion::Layout.new(self) do |layout|
      layout.view contentView
      layout.subviews :from, :subject
     layout.horizontal "|-15-[from]-[subject]-10-|", NSLayoutFormatAlignAllBottom
end
```