Implement my pseudocode

[gruppler]

http://gruppler.github.io/30DaysOfWebDev/day21/

This is a rough implementation of the following pseudocode:

for every row:
    for every cell:
        if "this" cell is empty:
            "peek" at the next cells until we find a non-empty one.
                if the next three are empty:
                    this is a good starting cell.
                if the next cell is also empty:
                    the cell after "this" cell is also a good starting cell.
                    etc.
                Otherwise, skip to just after the last non-empty cell we just "peeked" at