Make OS X .app bundling work with Qt 5.5.
macdeployqt doesn't actually seem to deploy any of Qt into the app
bundle, probably because we're using it in a fashion they didn't intend
(i.e., not doing everything with *their* build tools), so we just extend
our dependency-binding stuff to handle the Qt libraries, and copy over
the Qt plugins ourselves.
We also add the rpaths to the executables and libraries as part of the
app bundle building process; I thought it'd fix macdeployqt's problem,
but it didn't, however, it's probably cleaner to do it there anyway.
Change-Id: I134c2b1a32e168e82de67f0b674d17167481d69a
Reviewed-on: https://code.wireshark.org/review/9612
Reviewed-by: Guy Harris <guy@alum.mit.edu>