Limit the max number of POIs loaded
Limit the max number of POIs loaded

The param limit didn't have an upper border (just a default value). 
This will prevent a very simple DOS attack, using the limit with a very large number and running concurrently.
sozialhelden/wheelmap-open-source,sozialhelden/wheelmap-open-source,sozialhelden/wheelmap-open-source,sozialhelden/wheelmap-open-source