SF Patch #744104: Remove eval() from csv

SF Patch #744104: Remove eval() from csv

Eliminates the eval() step in the csv module resulting in better
security, more clarity, and a little speed.

The idea is to make successive attempts to coerce the string to
a python type:
    int(s), long(s), float(s), etc.

As a by-product, eliminates a bare 'except' statement.