next iteration of grid.py

[jerryu]

At present, grid.py has two iterations via the "exploratory process".

I wonder if another iteration would help future readers continue discerning the patterns.
Recognizing the grid as rows of repeated patterns, one may be able to restructure the code using a generalized 'row'.

By 'generalized row', I meant each row differs from each other, only by marker ('+' or '|') and filler('-' or ' '), hence its drawing can be encapsulated into one function with marker and filler as parameters.

[jerryu]

A pull request (#86) has been submitted to illustrate the abstraction of a generalized row.
any thoughts?