port to rw 1.9

Merge pull request #2 from casheww/1.9-port

1.9 port

dual fixes dual fixes

changes described by dual here:

#1

massive thanks to @Dual-Iron , you are epic

v1.1 - Tile Grid Lines

This release uses grid lines for tiles instead of nodes. This cuts the number of sprites, dramatically improving performance. Though I did prefer the tile nodes, this is the practical way forward...

First release

I hope the Rain World gods will forgive me

Please read the README before downloading