Update mapa.js

Improving "getPointsInBetween" function. Now you can ask for N points in between two geopoints.
Fixing mapa.js code: now it iterates over points and ask correctly for tracks to play in each point.
Merge pull request #1 from nigini/master

Update mapa.js: Improving "getPointsInBetween" function. Now you can ask for N points in between two geopoints.