Fix bug in ChaCha20 assembly code (was writing one byte too many).
Fix the assembly code to have APPLE format.
Change Poly1305 inline assembly as requested by compiler.
Initialize variables that will be set anyway - compiler complaint.
Change to use the assembly code files for Curve25519 and SHA-512.
Ed25519 not suported with ARM assembly.
1. Fix iOS Benchmark reference to the async.c file.
2. Fix iOS Benchmark reference to the sp.c file. Changed to spr_c64.c.
3. Removed misc.c from iOS Benchmark as it is using inlined misc.h.
4. Added define of HAVE___UINT128_T to the user_settings.h so the
benchmark would build.
5. Wrapped the benchmark usage strings in NO_MAIN_DRIVER.