Crop report plugin for NRL.

This plugin needs a custom version of mapfish-print and an instance of highcharts running.

This is a resume about the work:

* I've added a fireEvent 'refresh' inside Ext.ux.HighChart.js
* I've reused some code of CropDataButton and AgrometButton to a new ChartPanels
* I've deloped a mini framework to do this inside mapcomposer/app/static/externals/gxp/src/script/plugins/printreport directory.
* The button that uses it is NrlReportCropStatusChartButton.js
* I've updated the buildjs.cfg and mapStoreConfig.js to use it
* I've added a fieldset for the layout config