[Observium] PHP Weathermap Integration

Hi Guys,

We added PHP Weathermap into Observium ~2 years ago, but the enabling option wasn't documented because there was an odd javascript bug breaking the UI.

It turns out the bug was the same variable name being used in two completely separate bits of code, causing a clash. Typical Javascript.

This is fixed now and it mostly functions, so I've unhidden the enabling option in the web-based config.

$config['weathermap']['enable'] = TRUE;

It works slightly differently to the original weathermap, it generates maps on the fly and is a little better integrated into the UI. It retains all of the old issues though, the weathermap code is very, very old and should not be enabled on installs untrusted people have access to.

Thanks, adam.