Add future years and variables to widgets

Previously, the topic filters would only allow you to select years and/or variables for which data was available in the CropSignal database – making it difficult to configure widgets to also include future years/months/variables for when that data inevitably becomes available.  We have remedied this deficiency by adding ‘Add future’, ‘Show all variables’ -type checkboxes to the major Topics which, when checked, will include five future years that can be selected as well as all available variables/months that can be included in the selection as well.