plugin PositionChooser

Plugin to move quickly from a place to another.

Demo (internal at Camptocamp) on: http://admin-geospatial-suisse.gis.internal/bge_demo/
Or on this screenshot: 
![positionchooser](https://cloud.githubusercontent.com/assets/1792111/3887814/e69ca876-21f6-11e4-9c04-0870ef40adec.png)

(Search at the dropdown "Move to: [Places...      ]")

Do we want to expose the i18n strings as API parameters? That's not the recommended way to customize an i18n string (rather use the translation files).