[opus] Testing ARMv8 Ne10 and intrinsics branch

[Thomas Daede]

Using GCC 4.9.2, decoding the opus test vector set 10 times. All tests
pass. I will do longer tests later with a larger test set, but it looks
good so far.

I am having a lot of trouble with the Ne10 detection. Using the
precompiled Ne10 binaries at
http://people.linaro.org/~viswanath.puttagunta/opus/NE10_root/

Both NE10 and Ne10 capitalizations seem to be in use. Also, where should
the NE10 headers be installed? In $PREFIX/include or
$PREFIX/include/Ne10/? The configure.ac tests seems to assume the
former, but your precompiled root disagrees.

Opus master (36e0445)
Float: 20.312s
Fast float: 20.542s
Fixed: 17.402s

Opus rfcv1_final_xcorr_fixed_armv8 (eb95379)
Fixed w/ intrinsics, no ne10: 16.384s