Update README

README.txt

@@ -1,2 +1,6 @@
 TODO:
-— maybe make the explosion table function return a perlin explosion table
+* maybe make the explosion table function return a perlin explosion table
+* add documentation here instead of
+	https://dev.minetest.net/User:Hybrid_Dog#vector_extras
+* implement 3D scanline search
+* add vector.hollowsphere, less positions than WorldEdit hollowsphere