State: add new/free methods, plus module scaffolding
State: add smbclient_state_init()
State: add context auth function
State: smbclient_state_init now takes wrkg/user/pass arguments
State: make all exported functions context-aware
Dir functions: use PHP resource to track data
File functions: use PHP resource to track data
Add smbclient_state_errno() to query last errno for state
Merge pull request #4 from aklomp/state

Add state resource: must now register state first for effiency gains
Bump version to 0.4

State support introduced, thanks to Alfred Klomp.