[ros-diffs] [ion] 25885: - Merge DbgUnLoadImageSymbols from KD branch. - Rename LdrUnloadModule to MmUnloadSystemImage and: - Use MmSystemLoadLock. - Take into consideration the import list. - Honour load count. - Unload symbols if really unloading the image. - Dereference and clear imports. - Do proper LdrEntry cleanup. - Stub MiDereferenceImports and MmCallDllInitialize. - Implement MiLocateExportName and MiClearImports. - We don't yet fully support reference counting imports...this is still TBD.