changes to generate function to check missing tiles and predict gaps

initial commit for script to check missing tiles and predict gaps in mosaic: script part 0 global product assessment

experimenting with ffmpeg to generate movie from gif

modifying function to check missing files and dates for predictions and others

adding function to check missing predictions/mosaics

debugging function

adding plot animate raster time series in function script

generating animation for region 4 for multiple years sequences

generating animation for region 5 for multiple years sequences

generating animation for region 5 with and without range limit