Align result raster to exposure or hazard #344 #710

Helper function to adjust the clip extent to the edge of the pixels.

The following logic will be used:

* The clip extent of the **northern** edge will be **decremented** until it aligns with a pixel boundary of the target layer. If the target layer's northern edge is interior to the extents, the northern edge will be incremented until it aligns with a pixel boundary.
* The clip extent of the **southern** edge will be **incremented** until it aligns with a pixel boundary of the target layer. If the target layer's southern edge is interior to the extents, the southern edge will be decremented until it aligns with a pixel boundary.
* The clip extent of the **eastern** edge will be **decremented** until it aligns with a pixel boundary of the target layer. If the target layer's eastern edge is interior to the extents, the eastern edge will be incremented until it aligns with a pixel boundary.
* The clip extent of the **westernd** edge will be **incremented** until it aligns with a pixel boundary of the target layer. If the target layer's western edge is interior to the extents, the western edge will be decremented until it aligns with a pixel boundary.