Terrafold selling farm

[asl97]

If one buys way too much farm, progress slows down to a crawl which sucks.

Since it allow us to put in negative number, why forbid it?

stopsign.github.io/Terrafold/game.js

Lines 91 to 102 in 38680d6

	this.buyFarms = function() {
	var toBuy = Number(document.getElementById('buyFarmAmount').value);
	if(toBuy * 50 > this.land.soil) {
	toBuy = Math.floor(this.land.soil/50);
	}
	if(toBuy <= 0) {
	return;
	}
	this.land.soil -= toBuy * 50;
	this.farms.addFarm(toBuy);
	view.update();
	};

[Day-Elven]

There definitely should be a way to deconstruct farms.