Use smbclient so that it is possible to connect to Win7 systems.

The old code does not support the newer security models required for interoperability with Windows. Switch to smbclient, which works better and can be upgraded independently as required. If smbclient is not installed, the code will not find SMB shares, but it will still list NFS shares.

The .bb recipes should probably be updated to show that enigma2-plugin-systemplugins-networkbrowser now recommends samba.