Removed deprecated setScalesWhenResized

as of 10.6 this has no affect. see
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSImage_Class/index.html#//apple_ref/occ/instm/NSImage/setScalesWhenResized:
for additional details
Replaced deprecated convertScreenToBase

Replaced with convertRectFromScreen as suggested here:
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSWindow_Class/index.html#//apple_ref/occ/instm/NSWindow/convertScreenToBase:
Fixed `instance method not found` errors

In a few places casting `[NSApp delegate]` to `(SimpleComicAppDelegate
*)` fixes the `instance method '...' not found (return type defaults to 'id')` warning.
Added swipe to turn page
Merge branch 'warnings'
Merge branch 'deprecations'