[FEATURE] Add trackjserror option to piwik.

Add a new feature to enable tracking of uncatched JavaScript errors in the frontend in Piwik's Event tracking. This requires Piwik >= 2.2.0.
Also extended README a bit.
Changed some variable names in OpenStreetMap and additions..

$tmsserver was meant for the tile map server when we have coordinates.
The nominatim search server when we have just location, but no coordinates
Changed the URL parameters to OSM's current format.
Add option to view a marker on the map.

IMPORTANT: If you had set your own tmsserver or coordserver please check your configuration.
Merge pull request #26 from dawnbreak/master

New features for Piwik and OSM plugins.