Multi-monitor desn't work for config without screen

[Mulderua]

I just wanted to use my tablet on the second monitor. But found that is impossible because you have the next lines of code:

if not (main.settings['enable_multi_monitor'] and main.settings['screen']):
    return

So, If your tablet doesn't have a screen this option isn't available.

Workaround:
Add screen = true
Tou you tablet setting.

Anyway Thank you for this app

[joseluis]

Hmmm.... I should rethink this part.

#64 and #59 are probably related