GS282 - Mac OS library path to expat shared lib pointed to local machine

[ak19]

Some users reported that the 2.82 release contained a hard-coded path to a non-existent location for the expat .so file. It was pointing to a location on oranfry where the library file was that greenstone was compiled against.

The fix was to:

1. tell apache to configure, and therefore also compile up, the expat code that came with it. This way we could include a version of expat as part of the release that the LD_LIBRARY_PATH (DYLD_LIBRARY_PATH on Mac) could point to.

2. Setup.bash was modified to add the path to this expat library file ito the LD_LIBRARY_PATH for Linux and DYLD_LIBRARY_PATH for Mac.