Changes to allow for future division operator.

build.sh: remove automatic creation of test_example.py.
div_op.py: change documentation name from div_op to future_div_op.
runge_kutta_4_cpp.py: speed up not as good on a test system.
example.omh: add future_div_op to list of examples.
adfun.cpp: make sure CompareChange is defined before using.
pycppad.cpp: add comment about __truediv__ operator.
test_example.py: make new test_example.py a source file in repository.
Remove commit.sh (brad now uses one ~/bin/git_commit.sh for all projects).

.gitignore: test_example.py is now a source file, ingore junk files.
Move div_op.py to future_div_op.py.

pycppad.cpp: Fix move future_div_op doc from unary to numeric operator.
Start a new release not file. Use this one file for all future times
(becuase not so many notes that they need be separated by year.)

Comments for individual files go here, each line begins with: file_name at-sign