NtAllocateLocallyUniqueId
- implementation or stubs for NtAccessCheck, NtSetSecurityObject,
  RtlClearBits, RtlEqualPrefixSid, RtlFindClearBits,
  RtlFormatCurrentUserKeyPath, RtlGetControlSecurityDescriptor,
  RtlIdentifierAuthoritySid, RtlImpersonateSelf, RtlInitializeBitMap,
  RtlInitializeGenericTable, RtlMakeSelfRelativeSD,
  RtlPrefixUnicodeString, RtlSetBits, RtlUnicodeToMultiByteN,
  RtlUpcaseUnicodeStringToOemString, RtlUpcaseUnicodeToOemN,
  RtlValidSid, RtlxUnicodeStringToOemSize
- corrected most RtlString* functions, added documentation
- more fixes and partial implementations