windeployqt: Read more information from PE executables.

Read out debug information in order to be able to sort
debug/release plugins more cleanly.

Change-Id: Ia792064dca0a3beb3d671cf9a6175af8a5bf939f
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
windeployqt: Exactly match debug/release DLLs based on PE information.

Change updateFile() to be a template to be able to match files
with a predicate function and implement it for discriminating
debug/release DLLs. Reshuffle code, move findQtPlugins() to
main.cpp.

Change-Id: I75fe90ed2329a482d294abf6faeac700e1234167
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>