change max-width to width for the Bootstrap's grid

[bassjobsen]

The latest versions of Bootstrap use width in stead of max-width for the container which wrapped the grids.

This has to be changes in the css files which are include based on the "Max Container Width" setting in the customizer.

Note when full LESS integration has been finished, see also issue #82, this additional CSS files should not be needed at all

[bassjobsen]

container width and grid-float-break-point are now compiled in css by