initpyexpat(): Code cleanup; makes it more robust and reduces warnings.

initpyexpat():  Code cleanup; makes it more robust and reduces warnings.
                Added prototype to remove yet another warning.

Make a number of the handlers and helpers "static" since they are not
used in other C source files.  This also reduces the number of warnings.

Make a lot of the code "more Python".  (Need to get the style guide done!)