Add Hyperloop::Application

* Add simple hyperloop app fixture
Move app spec setup from before :all to :each
Make app#call get the file's HTML
Make app#call handle non-index requests
Handle 404s in app#call
Use local var for view path
Get rid of Application#views

* Just look up the file in Application#call
Move Application specs into flat context
Support subdirectories in app#call
Simplify app#call

* Get rid of unused ivars
Clean up app#call a bit

* Add Application#view_path(request)
Handle Application.new with no root
Merge pull request #1 from jakeboxer/application

Add main application class