Air Pollution Aerial:fix click-to-create-factories

[#69932484]

The click-to-create-a-factory feature was not working in Firefox, because the event handler relied on the nonstandard offsetX property of events, which is not implemented in Firefox.
Land Mgmt: fix cant-plant-perennials-twice bug

[#69727506]
Land Mgmt: fix jittering of eroder particles.

[#69726412]

The local variable 'direction' was not being copied back to the patch's property 'direction'. There was no good reason to maintain a separate 'direction' local, so I removed it.
Land Mgmt: make grass "lives forever"

[#69730884]
Land Mgmt: Nate's changes to Netlogo version
Land Mgmt: minimize edge effects in localSlope

[#69730958]
Land Mgmt: simplify erosion algorithm

[#69730958]
Land Mgmt: refactor erosion protection

[#69731272]
[#69731318]
Land Mgmt: decrease slope-slider range

[#69731212]

This avoids the "ledge" effect
Merge branch 'master' into topsoil-count-graph

Conflicts:
	land-management/app/src/erosion-engine.coffee
Land Mgmt: move topsoil count graph

[#69728404]