Replace tileset template

[WilliamFr0g]

SMBtiles is extremely lacking as an informative template, this one features useful examples of most tile properties
See also #568

Notable features include:

• Slopes and partial blocks, which are a pain to make from scratch
• Other unused properties such as vines, noteblocks, lava, and ice
• Functional smb-themed versions of some properties such as semisolids, water, spikes, and fences that only existed in often-tacky examples in portaltiles
• Placeholder squares on empty spaces to help with positioning

I considered removing the bowser bridge to save space, as I think most people don't really understand the bridge property, if they even use smb1 bowser at all, so I'd be interested to hear input on that. This tileset isn't meant to be comprehensive, but rather to provide a useful starting point (there is still a guide to the other less-useful properties in the game)