Support for non-x86 architectures (including ARM)

[tarcieri]

The gem is presently not packaged in such a way it will build on non-x86 architectures.

It shouldn't be too hard as it already packages the portable ref10 implementation, but some work will be required in e.g. extconf.rb

[armfazh]

I am preparing the implementation using native 64-bit instructions for pre-Haswell processors.
According to my experience, the performance will be affected in comparison to the Haswell implementation, but I predict a faster execution in comparison to ref10.

[dentarg]

@tarcieri mind doing a release with the latest improvements in this area?

[tarcieri]

Released as v1.0.10

[dentarg]

Thanks!

[tarcieri]

Fixed by #36