intel-intrinsics v1.2.0: Added GDC support, SSE3

[Guillaume Piolat]

`intel-intrinsics` is a DUB package for people interested in x86 
performance that want a portable set of intrinsics which works 
with all D compilers.

Available through DUB: 
http://code.dlang.org/packages/intel-intrinsics


*** Changelog of v1.2.0 ***

- SSE3 intrinsics were implemented.
- Added GDC x86/x86_64 support


See this table here to know in which case the intrinsics resort 
to a slow, emulated version: 
https://github.com/AuburnSounds/intel-intrinsics#supported-instructions-set