Concatenates titles and info of programs that have the same location.

If several programs had the same location, the latest marker would cover the earlier markers. The earlier markers would not be show to users. This patch modifies the drawMarkers function to check for markers with the same location. When they are found, the function concatenates the titles and contentStrings of the markers. The result is that one marker is generated for programs with the same location and all names and contentStrings are displayed in one infoWindow, thus showing all programs to users. Using verbose comments to help other users, per Stephen's style.