Fix to jobs indicator reprojection & calculation.

Removed a warp call that was behaving funny and not actually doing any good. Not sure why the `Tile.warp(Extent, Extent)` call was not cropping and instead funking out the raster...I wrote a GeoTrellis ticket to look into that.

Also changed the jobs indicator to be a calculation of 'what sum of the population can get to a place by an arrival time in the amount of time specified in the duration', instead of 'what are the number of jobs that could be arrived at by the arrival time by someone leaving from an area and traveling for no more then the specified duration.'