Raster export and import

Allow the use of rasters for importing and exporting data. Rasters take up significantly less space than a vector file and require less pre and post processing. Spatial layers like roughness, 2D hydraulic conditions, Infiltration, etc. could be imported a raster rather than a vector. Most importantly results from the 2D mesh should be able to be exported as a raster, producing smaller output files that are significantly easier to load within and outside of the software. This would save significant time and would show that ICM can compete with other modelling software providers that already have this option. Many clients are wanting more and more 2D models.