The Stitcher base trait.
Stitch an Iterable of tile, corner pairs into a new tile with
the given number of columns and rows.
The parameter 'pieces' is an iterable of (T, (Int, Int)) tuples,
were the first item in the tuple is a tile and the second one is
the position that the tile should occupy (given by smallest
column and smallest row).
An iterable of tile, corner pairs
The number of columns in the result tile
The number of rows in the result tile
The result tile