wbemprox: Implement Win32_ComputerSystem.NumberOfLogicalProcessors and Win32_ComputerSystem.NumberOfProcessors.

While we're allowed to leave the device in a somewhat inconsistent state after
a failed reset, such a state should be recoverable by calling reset again. If
e.g. mode setting were to fail between the point where we destroy and recreate
the stateblock a subsequent reset would crash because the device doesn't have
a stateblock anymore.

It takes a good 0.5 seconds for MPEGSplitter_pre_connect to iterate over the
file and build the table for a standard 2 or 3 minute MP3. This causes
unsightly hiccups when an app tries to play a new file, particularly in games,
as the pre-connect needs to happen synchronously to tell whether it can
succeed or not.