Added new command /path:follow to create a path wherever the player walks.

Usage: `path:follow <start|stop> [radius] [path material]` (aliased as `pf`) where [radius] is a number between 0 and 5, and [path material] is any solid block. NOTE you must run path:follow stop to tell Pathinator to stop creating a path wherever you walk.

For example, `path:follow start` will start following using the default radius and whatever block you are currently standing on. `path:follow start 2 minecraft ak_planks` will create a wide path with OAK_PLANKS.