All polygons in one area + dedups states

All areas are merged.
Polygons and circles are put inside a single area element.

Additionally, state list for the "estados" parameter is now built
using a hashset to avoid duplicate state IDs.

Fixes #186
Move list of states to "areaDesc" & cyclone direction to "trayectoria"

Enhancement to Fix #186
Cambio a nombre de variable para trayectoria
Remueve el param "estados" ya que es duplicado de "areaDesc"
Merge pull request #187 from mxabierto/merge-areas

Mete polígonos dentro de un mismo campo <area>
Add <area> to <info> only if some regions in the map were drawn at step 1.
Fixes #143.
Add areaDesc no matter what
Merge pull request #194 from mxabierto/feature-generatecap-dp

Add <area> to <info> only if some regions in the map were drawn at step 1.
Trim bounding box
Check if trimmed bbox contains a drawn polygon
Merge pull request #196 from mxabierto/trim-bbox

Trim bounding box