make autogen executable
use __asm over asm for c99/portability
correct misnamed loop variable for ARM NEON path

see original source for details: https://github.com/floodyberry/supercop/blob/master/crypto_stream/chacha20/krovetz/vec128/stream.c#L152
stub in a dummy rdrand test function for non x86 systems

this test is already guarded with a check for OTTERY_CPUCAP_RAND
Merge pull request #13 from busterb/master

A couple of minor fixes to make embedding as an automake subproject easier