pyobfsproxy rename necessitates different bundle App directory structure

Since the program name is now "obfsproxy", it conflicts with the Python module of the same name. Before 3b80ce41 we had this structure in bundle App directories:

pyobfsproxy*
obfsproxy/

But now we can't do that because the names are the same:

obfsproxy*
obfsproxy/

Some options:

1. Call the executable obfsproxy.bin only in the bundles.
2. Put the obfsproxy executable in bin/obfsproxy in the bundles.