Error message if google maps api is not loaded

[easyest]

There should be a message if OMS is loaded without google maps api. ATM the script silently dies.

[TheTerrasque]

Sweet Jesus! Thank you, I finally figured out why the code wouldn't work!

Not giving any error and just die silently is a terrible design.

[easyest]

It seems the project is long dead...

[jawj]

Nope, I'm just really busy! I'll certainly consider a pull request on this one.