Convert from numbers to letters

[Steven Bethard]

Jason Drew wrote:
> ##def tuple2coord(tupl):
[snip]
> ##    rowfromzero, colfromzero = tupl

Just a side note here that if you want a better function signature, you 
might consider writing this as:

tuple2coord((rowfromzero, colfromzero)):
     ...

Note that the docstrings are nicer this way:

py> def tuple2coord(tupl):
...     x, y = tupl
...
py> help(tuple2coord)
Help on function tuple2coord in module __main__:

tuple2coord(tupl)

py> def tuple2coord((x, y)):
...     pass
...
py> help(tuple2coord)
Help on function tuple2coord in module __main__:

tuple2coord((x, y))

STeVe