Issue #535: fix nose.importer to work when the same modules are reachable from different paths along sys.path, due to e.g. symlinks.
(note: not sure this will work under Windows, this may need further tweaking)
Fix tests under py32 by creating the symlink dynamically (it didn't get copied into build/tests).
Also, try to make things work under Windows (but untested).
Replace abspath() with realpath(), and remove redundant call to normpath()
Merge pull request #601 from pitrou/issue535

Issue #535: fix nose.importer to work when the same modules are reachabl...