Added ability to copy area of tiles from tile selection

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// Another update

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+Added the ability to copy an area of tiles from the tile selection(though there's no outline to show it happening just right click and drag)

+Added ability to change brush size from the toolbar

+Added information to the help and README(forgot to mention WASD moves camera previously)

+Improved how collision is handled between the first 2 layers(placing a tile with no collision will no longer remove collision on other layer)

+Fixed a couple bugs 

+Made another version that stores several maps in one file I may release soon.