libs: shramov leaflet plugins added as library (release 1.0.0 as is without compilation)
layers: adding permalink to location using leaflet-plugins (and clean up order of linking JS and CSS)
libs: Leaflet.Coordinates (MrMufflon) added as library (release 0.1.3 source code as is)
layers: showing coordinates and improving style of permalink
updating 3rd party code in readme
layers: adding gray scale tile OSM layer (using toolserver.org tiles)