[FLTMGR]

[FLTMGR]
- Implement basic versions of FltRegisterFilter and FltUnregisterFilter
- Add layout of data for FLT_FILTER, FLT_INSTANCE, FLT_OBJECT and their accociated data
- Add basic rundown protection for the FLT_FILTER object
- Removed from the build for now because GCC doesn't like our fltkernel.h header

svn path=/trunk/; revision=71859