Changed the interface.

The parameter user was moved from connect() to the constructor, so every
connection belongs to a certain user.
Command poll interval reduced.

Reduced the poll interval in execute() from 1000ms to 100ms.
execute() now takes a list as args.

Changed the signature of execute, it now takes a list as the args
parameter instead of a command string and converts it to a command
string on its own with subprocess.list2cmdline().
First actual implementation.