Update library to work with Python 3

[symbioquine]

I've only tested the read-only methods so far, but this version seems to be working for me.

[sanitariu]

I've only tested the read-only methods so far, but this version seems to be working for me.
Did you ever succeeded in making for example setlimit change ampers ?

[symbioquine]

I've only tested the read-only methods so far, but this version seems to be working for me.

Did you ever succeeded in making for example setlimit change ampers ?

No, my use-case is just read-only and I haven't wanted to risk messing up the settings on my $1200 inverter just to test this.

[martinling]

In case this is useful: I can confirm that set_assist works correctly with @symbioquine's version.