Various on qt4-mac

[Michael Dickens]

First cut at the 'select' files, and where they end up.  Abbreviated
version:

libexec/qt4-X/bin/*.app                   -> ${applications_dir}/Qt/
libexec/qt4-X/lib/*.framework             -> ${frameworks_dir}/
libexec/qt4-X/bin/*.app/Contents/MacOS/*  -> ${prefix}/bin/
libexec/qt4-X/bin/*                       -> ${prefix}/bin/
libexec/qt4-X/lib/pkgconfig/*             -> ${prefix}/lib/pkgconfig/
libexec/qt4-X/share/doc/qt4-X             -> ${prefix}/share/doc/qt4
libexec/qt4-X/share/qt4-X                 -> ${prefix}/share/qt4

NOTES:

* The Frameworks don't actually need to be selected, but I'm doing so
for the sake of backwards compatibility with the current Portfile. 
Frameworks are found in the pkgconfig files correctly, and I think it's
reasonable to expect that anyone #include'ing or linking into Qt will
use pkgconfig given how complicated access to Qt stuff is.  Once I've
explored ports that depend on qt4-mac, to make sure they still work,
I'll determine whether or not the Frameworks can be ignored by 'select'
& remove them if possible.

* No 'include' files or directories are selected, since (again) they are
determined by the pkgconfig files, and there is no backwards
compatibility to maintain from the previous Portfile.

* For qt4-x11, qt4-x11-devel, and qt4-mac-devel: Not all of the above
will be used, and there might be alternative files / directories to be
included.  I'm building the X11 basic version now, and will check once I
can 'destroot' it; likewise for the devel versions, one at a time.

* Using 'select' eliminates much of the 'post-destroot' internal
linking, since that's now handled externally.