Add New Method to Gridmaker Module

New ‘zoom’ method added. Allows setting and getting the zoom level of
the map.
Fix Gridmaker Zoom Assignment
Add Get Static Map Image for Region

New method: getRegionStaticMapByIndex returns static map for the
selected region.

Work in progress: accurately calculating zoom level of returned static
map images.

Fixed: clear grid was not wiping out the _regions array.
Create Demo

Started work on the Demo page