Replace CrLf with just Lf, and let Python do the right thing
LeetCode source code always seems to have CrLf. We need to change that
to just Lf and then let Python do the right platform-specific thing
when writing it out to the text file. Not doing this causes a problem
on Windows where the code seems to have double the number of newlines.
Use the right extension for Python solutions
We were simply using the language name as the extension for the file.
This works fine for C++ (cpp) and Java, but not for Python.