grid: Add NewMap function, Location type and Loc helper function.
view: Add package view which supervises the visible portion of the screen.
cmd/world: Add example tile set from tile engine tutorial.

ref: http://www.xnaresources.com/?page=Tutorial:TileEngineSeries:1

Any copyright associated of the example tile set is held by xnaresources.
cmd/world: Add world command which renders the game world.