WIP: make install and make package works on Mac OS.
Cleanup.
Packaging is now enabled by default.

There is no reason why it should not.
Default packaging on Windows is zip.

Switching to NSIS packaging on Windows via OGS_PACKAGING_NSIS=ON.
Added script for getting the Visual Studio installation path.

This is useful for finding Visual Studio tools such as dumpbin.
Fixes for Windows packaging.
Run CMake after gui was first built to get dependent shared libs.
Removed unnecessary line.
Install XML schema files into the Mac bundle.
Added the logo to the Mac installer.
Merge pull request #287 from bilke/Packaging

Packaging on Mac OS