- Add KF_XMMI64 feature flag for SSE2 and detect it.

- Add KF_XMMI64 feature flag for SSE2 and detect it.
- Detect Hyper-Threading and set Local APIC ID (put back Thomas's code that he added in an old revision and that I had accidentally removed and forgotten to re-convert into the new KiGetFeatureBits function).
- Add code to set the kernel MX Csr Mask in the FX Save Area.
- Startup the sysenter handler on the DPC stack.
- Detect and notify users with broken Pentiums.
- Do some NPX checks to forcefully disable any FPU flags that might be set (SSE, MMX, 3DNOW) if the NPX is disabled.

svn path=/trunk/; revision=24386