volk: replace assembly and separate cases with gcc cpuid for all x86
A fix for volk_cpu being a duplicate variable. Declared as extern in the header file volk_cpu.h and actually created in the C files.
Note that this could be a problem if multiple architectures are ever (can ever?) be built at the same time. If that happens, we can move this variable declaration to another C file that is made common to all builds.
volk: fix for running 32-bit OS on 64-bit processor. System is correctly identified as 32-bit and compiles with the correct flags.
Initial checkin for VOLK - Vector-Optimized Library of Kernels. This is a new SIMD library.
It currently stands by itself under the GNU Radio tree and can be used separately. We will integrate the build process into GNU Raio and start building off of its functionality over time.