fix(olHelpers.js): use HTTPS Mapbox URL (#338)
fix(olHelpers.js): use HTTPS Mapbox URL (#338)

This addresses issue #337. It is a one-character change, changing the protocol from http to https.
gaf-ag/angular-openlayers-directive,tombatossals/angular-openlayers-directive,ageblade/angular-openlayers-directive,polesapart/angular-openlayers-directive