[wms] - some more token related stuff
[wms] - manifold wms related token checkup calls
[wms] start gdal based simple raster wms
[wms] - gdal based wms get map seems to be ok
[wms] - refactoring the wms utils so can be used with many drivers

this is so the utils can be used for manifold driver, gdal driver, etc.
At this stage not sure yet, which one is gonna be used, perhaps both
depending on the final setup(s)