now bin and share are not pegged to linking the executable any more,
but are proper subdirs targets of their own.
unforturnately, qmake is a bit tenacious, so we hack around a bit. :)

more or less in passing by, i removed some superfluous trailing slashes
and added path normalization as well.

Task:     Reported by Roberto
RevBy:    TrustMe
Details:  Plugins still don't load on Mac.

Details:  Creator on Linux works now in two modes:
          1) out of the build dir (shadow builds to be tested)
          2) make INSTALL_ROOT=/prefix install

Details:  Make install works now, we just have to agree on layout
details and check for mac compatibility.

Also, plugins will carry no version in their filename anymore starting with
this commit. Versioning happens in the creators pluginloader using the pluginspec file.