Perform proper checking for share availability

To check for shares, the code attempts to connect anonymously to the share.
In most cases this will fail with NT_STATUS_ACCESS_DENIED, so the regex array
used for parsing the output of smbclient in smb4php has been overridden to
treat such output as success.

The 'test' method for storage classes can now take a single parameter,
$isPersonal, which allows the storage to adjust the tests performed based on
if they are being configured as personal shares or as system shares.