Last night I did manage to upload a build to iTC using the application loader, however Xcode 7.1 still has the same issue though.
The steps i followed are as follows
Step 0 - Deleted Xcode 7.1 ( which was upgraded from previous version of Xcode 7.0.1 from MAS). Downloaded a fresh copy of xcode from MAS.
1. Revoked my distribution certificate
2. Recreated the distribution certificate from Xcode
3. Re-generated all provisioning profiles to use new distribution certificate
4. Cleaned build folder.
5. Updated the build version.
6. Archived product from the Xcode's product menu
7. Tried validating and uploading the build from Xcode (failed)
8. re-did steps 4 to 6 and exported the .ipa from Organizer screen
9. Started 'Application Loader' and choose the ipa to upload. (success finally)
I also did notice that the application loader based process had failed as a containing framework had a non dot separated version string . i.e The Hockey SDK in my build had a version 3.8Beta-1. Updated to the latest hockey sdk to version 3.8.4 and was able to upload my build to iTC using application loader (Yes, I did try the upload with xcode and it failed with the same message from my previous post. "You are not authorized to use this service")