Fix framework bundle deployment

Rework copyFramework(). Split out dylib deployment
into copyDylib(). Remove the special symlink handling.
Always create symlinks from "Current" to the actual
version.

This ensures we're compatible with Apple's framework
bundle spec [1]. It also makes the 'codesign' utility
happy, easing the step to sandbox Qt OS X applications.

[1]: https://developer.apple.com/library/mac/documentation/


macosx/conceptual/BPFrameworks/Concepts/FrameworkAnatomy.html

Task-number: QTBUG-32896
Change-Id: Ide23437c9bb6515d5013d37ae6ff4133a69085ad
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>