To deal with params, the following methods are available:
* `getParams`: returns all params
* `setParams`: used to update the values of some params

Three OpenLayers Map events are also available:
* `changeparam`: launched with the changed params values
* `changeparamsready`: launched when the application is ready to receive
* `dochangeparams`: used to call for `setParams` without knowing the current object.

Events are passed through the map in order to be able to create an OpenLayers Controller that uses the params without any dependencies on Sencha Touch, required by a project component.