Added new Task to insert colours into a VRT file

Caters to both catagorical and continuous datasets, does not do proper xml parsing and could probably do with some improvements in that regard
Added new Task to run the gdal2tiles.py utility
Can now specify the expands and scale parameters

Necessary arguements for WMTS Tile generation. Scalar receivers are used to pass scale parameters in from other tasks
Can now specify a single source file as an input to translator

Previously a list of TileBand objects was required
finished task pipeline for the WMTS Tile generator application

Seems to work, albiet in isolation for now