BundleUtilities: Use 'find' on UNIX for fast executable lookup

It makes whole executable process quicker on UNIX, especially for large bundles
containing many files, since using find narrows results to only files having
executable flags then all further tests follow.
GetPrerequisites: Make sure dyld placeholders are prefixes

Mac OS X dyld placeholders should be always prefixes, otherwise this can lead
to some undefined behavior.
BundleUtilities: Resolve & replace @rpath placeholders

This is done by gathering LC_RPATH commands for main bundle executable and
using it for @rpath lookup in dependent frameworks.

To achieve this all utility functions now take path to executable rather than
path to its directory.

This enabled apps using @rpath to be bundled correctly, which will be necessary
for upcoming Qt 5.4 that will use @rpath for all frameworks.
BundleUtilities: Process executables first when scanning bundle

This makes rpaths populated (if any), so libraries containing @rpath will be
resolved properly.
BundleUtilities: Codesign needs framework's Contents/Info.plist

Therefore we need to bundle it (if present) too when fixing Mac OS X app bundle.
cmake-gui: Make sure we bundle Qt5 Cocoa platform plugin

Otherwise CMake.app bundle will not run when using Qt5.
Merge topic 'bundle-updates' into next

c106311f cmake-gui: Make sure we bundle Qt5 Cocoa platform plugin
bd67c3ea BundleUtilities: Codesign needs framework's Contents/Info.plist
ea9e35be BundleUtilities: Process executables first when scanning bundle
7747b13e BundleUtilities: Resolve & replace @rpath placeholders
195ec6b3 GetPrerequisites: Make sure dyld placeholders are prefixes
02dfaa31 BundleUtilities: Use 'find' on UNIX for fast executable lookup