winpr/sysinfo: added IsProcessorFeaturePresent and IsProcessorFeaturePresentEx

These functions can be used to check if an processor feature is supported.
IsProcessorFeaturePresentEx is a extended version which is not available
in the windows API and allows to query additional features.
Currently it works on the following platforms:
- i386/amd64 when compiling with gcc
- ARM on linux
codec/rfx: use sysinfo to detect sse2/neon

This also moves (sse2) detection code out of the client into the decoder.
primitives: make use of winprs processor feature detection

- Removed the cpu flag detection
- Fixed and updated the tests
codec/rfx,primitives: removed cpu-detect.[ch] from build

sysinfo cpu detection is used on android as well.
primitives: updated tests, cleanup and build fixes
IPP: disable on arm and apple
primitives: removed build warnings on arm
sysinfo: neon is supported on all current ios devices
primitves/test: use Ex function for extended flags
winpr/sysinfo: restructuring and "aliases" added

Added meaningful aliases for the not so clear defines.
primitives: use alias define for SSE2
primitives: fixed flag detection for sign functions
iOS: set CMAKE_SYSTEM_PROCESSOR in toolchain file

This is required that the right architecture is chosen during the cmake run.
Otherwise it is not possible to compile WITH_NEON.
Merge pull request #1023 from bmiklautz/cpuflagdetection

CPU feature detection