feat(olHelpers.js): Support for Multiple Tile Server in XYZ Tile Layer (#392)
feat(olHelpers.js): Support for Multiple Tile Server in XYZ Tile Layer (#392)

This is the code enhancement for Issue #391.
tombatossals/angular-openlayers-directive,polesapart/angular-openlayers-directive,gaf-ag/angular-openlayers-directive