fix for scenarios in which there is no auth token secret. For instance in step 1 of reverse auth. Prior to this fix the signing key had '(null)' appended to the end and the signature was invalid every time
added an oauth authorization header generator that takes into account the 'oauth_callback' parameter
Cleanup formatting
Preserve trailing slash in signature base

This patch changes the library to preserve the trailing slash when computing
the signature base string.

-[NSURL path] function always excludes a trailing slash. Since the oauth specification
makes no mention of excluding a trailing slash, it seems correct to preserve it. At least
one python server-side library will not accept requests without this patch.
Update ab_actualPath to use CFURLCopyPath

This should be a little more reliable
Add project

for easy use as lib
Remove active-arch-only from proj

for cmdline builds
Merge branch 'master' of https://github.com/socialize/OAuthCore