When overriding grid-float-breakpoint to a larger size, dropdown menu still has desktop styling.

Created by: bpugh

The docs say to customize the @grid-float-breakpoint variable for the point when the navbar collapses, however the dropdown menu styles use the @screen-xs-max which means that if for instance I set the grid-float-breakpoint to 1000px the dropdown menu will have the desktop styles after 767px.

So I created a grid-float-breakpoint-max to use for the dropdown styles so it behaves more consistently when customizing the grid-float-breakpoint. I hope that makes sense.