Added the possibility to log virtual key codes

[AbsoluteVacuum]

Each key can now be logged as a code in dec or hex, which can be used for lookup. Can be useful for debugging. Previously log file would have a lot of NULs, so had to see what keys were actually pressed. MSDN table (https://docs.microsoft.com/en-us/windows/win32/inputdev/virtual-key-codes) uses hex, other web resourses may use dec. All the default behaviour of Save() is preserved if FORMAT is defined as 0.

[GiacomoLaw]

Thanks for this and apologies for the delay in merging.