smbclient_option_(get|set): add functions
Options: add some basic testcases
smbclient_option_(get|set): add documentation
Options: tests: add NTLM hash test; change guest access to "no"

For the NTLM hash test, we need to set the "guest access" flag in the
Samba setup to "no", otherwise we're allowed to connect anonymously.
smbclient_(library_)version: add functions, documentation and tests
smbclient_(f)statvfs: add functions and documentation