Remove vector assertions

These were initially added to get tracebacks for invalid vector errors, but it
didn't work and tracebacks have since been properly fixed in the core.

builtin/common/vector.lua

 
 vector = {}
 
-local function assert_vector(v)
-	assert(type(v) == "table" and v.x and v.y and v.z, "Invalid vector")
-end
-
 function vector.new(a, b, c)
 	if type(a) == "table" then
 		assert(a.x and a.y and a.z, "Invalid vector passed to vector.new()")
@@ -17,20 +13,16 @@ function vector.new(a, b, c)
 end
 
 function vector.equals(a, b)
-	assert_vector(a)
-	assert_vector(b)
 	return a.x == b.x and
 	       a.y == b.y and
 	       a.z == b.z
 end
 
 function vector.length(v)
-	assert_vector(v)
 	return math.hypot(v.x, math.hypot(v.y, v.z))
 end
 
 function vector.normalize(v)
-	assert_vector(v)
 	local len = vector.length(v)
 	if len == 0 then
 		return {x=0, y=0, z=0}
@@ -40,7 +32,6 @@ function vector.normalize(v)
 end
 
 function vector.round(v)
-	assert_vector(v)
 	return {
 		x = math.floor(v.x + 0.5),
 		y = math.floor(v.y + 0.5),
@@ -49,8 +40,6 @@ function vector.round(v)
 end
 
 function vector.distance(a, b)
-	assert_vector(a)
-	assert_vector(b)
 	local x = a.x - b.x
 	local y = a.y - b.y
 	local z = a.z - b.z
@@ -58,8 +47,6 @@ function vector.distance(a, b)
 end
 
 function vector.direction(pos1, pos2)
-	assert_vector(pos1)
-	assert_vector(pos2)
 	local x_raw = pos2.x - pos1.x
 	local y_raw = pos2.y - pos1.y
 	local z_raw = pos2.z - pos1.z
@@ -89,9 +76,7 @@ end
 
 
 function vector.add(a, b)
-	assert_vector(a)
 	if type(b) == "table" then
-	    assert_vector(b)
 		return {x = a.x + b.x,
 			y = a.y + b.y,
 			z = a.z + b.z}
@@ -103,9 +88,7 @@ function vector.add(a, b)
 end
 
 function vector.subtract(a, b)
-	assert_vector(a)
 	if type(b) == "table" then
-	    assert_vector(b)
 		return {x = a.x - b.x,
 			y = a.y - b.y,
 			z = a.z - b.z}
@@ -117,9 +100,7 @@ function vector.subtract(a, b)
 end
 
 function vector.multiply(a, b)
-	assert_vector(a)
 	if type(b) == "table" then
-	    assert_vector(b)
 		return {x = a.x * b.x,
 			y = a.y * b.y,
 			z = a.z * b.z}
@@ -131,9 +112,7 @@ function vector.multiply(a, b)
 end
 
 function vector.divide(a, b)
-	assert_vector(a)
 	if type(b) == "table" then
-        assert_vector(b)
 		return {x = a.x / b.x,
 			y = a.y / b.y,
 			z = a.z / b.z}