more debugging of mask and testing of code

fixing mask used and no data values

adding compression and debugging for valid range and rescaling of mosaicing

valid value range with gdal calc in mosaic function

adding valid range parameter for mosaicing function script

listing of files using glob and minor clean up to mosaicing function script

adding use int and scaling option to function mosicing script

adding valid range option to master script mosaicing

modification of master script mosaicing stage 7 adding use integer and scaling option

stage 7 mosaicing, major clean up and modification to allow call from shell for jobs on NEX