Tidy OS X project - reorder files into alphabetical order
Xcode Project - Universal Binaries

Create architecture-specific includes for curve25519-donna[-64].c.
Add dependencies between the various components.

The project uses configure to generate orconfig.h for x86_64 & i386,
make to build micro-revision.i, common_sha1.i, and or_sha1.i, and
Xcode to build universal binaries for tor, bench, and test*.

Known Issues:
HomeBrew won't work until I move configure arguments out of the project
(into an editable script?) and source header & library paths from
configure/Makefile.
test can't find test-bt-cl, test-ntor-cl, and test-child due to path issues
(these tests currently fail).
There is no README or changes file yet.