add proper ships

[matthewcarleton]

We should have
1 x 5 cells
1 x 4 cells
2 x 3 cells
1x 2 cells

As long as this isn't too many for the 5 x 5 grid, if so we could drop it to
1 x 5 cells
2 x 3 cells
1 x 2 cells

@burrsutter WDYT?