NDVI statistics training doc

Page for the training on this module. This commit fixes #22 issue.
Merge branch 'issue_22_stats' of git://github.com/alediator/crop-information-portal into alediator-issue_22_stats
Merge branch 'master' of github.com:geosolutions-it/crop-information-portal
fixed link and figures in complete example
add geobatch config tutorial
Merge branch 'master' of github.com:geosolutions-it/crop-information-portal