added an UMD style wrapper:
added an UMD style wrapper:

Used the [returnExportsGlobal](https://github.com/umdjs/umd/blob/master/returnExportsGlobal.js) variant.

google/open-location-code,google/open-location-code,chlorm-forks/open-location-code,chlorm-forks/open-location-code,zongweil/open-location-code,bocops/open-location-code,zongweil/open-location-code,zongweil/open-location-code,bocops/open-location-code,zongweil/open-location-code,wnameless/open-location-code,zongweil/open-location-code,wnameless/open-location-code,chlorm-forks/open-location-code,bocops/open-location-code,chlorm-forks/open-location-code,bocops/open-location-code,google/open-location-code,wnameless/open-location-code,bocops/open-location-code,google/open-location-code,bocops/open-location-code,google/open-location-code,chlorm-forks/open-location-code,wnameless/open-location-code,google/open-location-code,google/open-location-code,bocops/open-location-code,bocops/open-location-code,zongweil/open-location-code,bocops/open-location-code,wnameless/open-location-code,wnameless/open-location-code,bocops/open-location-code,google/open-location-code,chlorm-forks/open-location-code,wnameless/open-location-code,zongweil/open-location-code,zongweil/open-location-code,google/open-location-code,chlorm-forks/open-location-code,google/open-location-code,zongweil/open-location-code,bocops/open-location-code,google/open-location-code,zongweil/open-location-code,zongweil/open-location-code