Fix devices not mapping if there are no partitions

[bclindner]

In AlarmController.async_update, the mapping loop prevents accounts with no partitions from being mapped, since the loop would only run if you had at least one partition. We can resolve this by handling the device mapping after the partition mapping, rather than during.

If I had to guess, it looked like there was a reason this was done. Without this, though, this library and the Home Assistant component are unusable unless you're able to set up a partition (and since my setup is actually managed by my apartment, I can't). If a user who has partitions could try this on their side to verify everything is OK before merge, that would be appreciated.

[bclindner]

Closes #124.

[andnp]

Bumping this PR. I just went through the same set of fixes and was about to put up an equivalent PR because home assistant no longer sees my devices.

I tested these changes locally in my home assistant install and they work for my particular setup. Like @bclindner my apartment manages my alarm.com account and so I cannot test with partitions.

[elahd]

Thanks!