Update map.html and shp.js

I updated map.html because it was not functional.  When I updated it, I realized that the shp.js DBF tools were not truncating the null characters and trailing whitespace left from the archaic DBF format.  I added two simple regexs to the shp.js to combat this issue.  There may be a better way to do it, but I'd like to at least suggest the change.

Thanks for your hard work on this project!  I did a similar shp/dbf parsing project years ago in C++ (it's in my github somewhere at the bottom), so I have some some experience with parsing shapefiles. I'd be glad to collaborate with you more on this project or similar ones.

--
Jim McAndrew