Common: Add a generic class for accessing bitfields in a fast and endianness-independent way.

The underlying storage type of a bitfield can be any intrinsic integer type,
but also any enumeration.

Custom storage types are supported if the following things are defined on the storage type:
- casting 0 to the storage type
- bit shift operators (in both directions)
- bitwise & operator
- bitwise ~ operator
- std::make_unsigned specialization

Source/Core/Common/Common.vcxproj

@@ -46,6 +46,7 @@
     <ClInclude Include="Atomic.h" />
     <ClInclude Include="Atomic_GCC.h" />
     <ClInclude Include="Atomic_Win32.h" />
+    <ClInclude Include="BitField.h" />
     <ClInclude Include="BreakPoints.h" />
     <ClInclude Include="CDUtils.h" />
     <ClInclude Include="ChunkFile.h" />
@@ -143,4 +144,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
+</Project>