freeldr: Add support for SSE instructions

Note: This is not in any way x64 related!

Currently the x86 version of freeldr crahses, when the compiler generates SSE instructions.
Therefore we need to disable generation of SSE code globally.
Older MSVC versions default to no SSE, but since VS11 the default is using SSE.
We disable that by adding /arch:IA32 for MSVC versions >= 1700 (root CMakeLists.txt)

Desired:

• Initialize the cpu in freeldr, so that SSE is enabled, if the cpu supports it
• globally enable SSE if the target processor supports it