markers near route

This version introduces multiple enhancements:

added list of group markers
show markers from selected group near founded route

for development, retrieve coordinates of point that user click on map

Details of additions/deletions below:
--------------------------------------------------------------

Added:      img/group1.png
Added:      img/group2.png
Added:      img/group3.png
Added:      img/group4.png

Added:      js/markers.js
            -- Added --
                list of groups with their markers

Added:      js/vendor/RouteBoxer.js
            -- Added --
                library to detect area near find route

Modified:   index.html
            -- Added --
                form with list of marker groups
                some required scripts
                block for coordinates

Modified:   js/maps.js
            -- Added --
                functions to return coordinates fo clicked by user point
                place on map markers from group and display markers that are near route

Modified:   css/maps.css
            -- Added --
                styles for list of marker groups