Write sum to a new file
Added name ('Sum') to new file
Don't warn about new file changes when closing
Set new file to read-only

Since the new file does not prompt about file changes when closed, if
the user were to edit the new file and close without saving, their
changes would be lost forever. By setting the new file to be read-only,
the user will not be able to make changes to it that may be lost.
Change `new_view` to `sum_view`

`sum_view` is a more descriptive variable name.
Conform to PEP-8: Use 4-space indents
Echo file contents to new file
Add up all ints (base 10) and floats in the file