boolean System_WinDrives::isApiAvailable (
Checks if the API methods to read the drive list are available, and returns that.
They may not be available if the necessary extensions (win32api on PHP4, php_ffi on PHP5) are not installed on the system.
If the API is not available, the drive list is brute-force guessed. Drive types are not available in that case.
boolean - true if they are there, false if not.