Delete deprecated optparse code

[tleonhardt]

For the 0.8.0 release of cmd2 on February 1, 2018 we officially deprecated all usage of the optparse module within cmd2 and replaced it with argparse-based decorators.

We should plan to delete the deprecated optparse code some time soon, perhaps in either the 0.8.3 or 0.8.4 release.

Any opinions regarding when this code should get deleted?

[tleonhardt]

Ok, unless there are any objections, lets target deleting the old optparse code for the 0.8.4 release.

[kotfu]

No objections here.

[tleonhardt]

@kmvanbrunt Do you anticipate any negative end user impact if we delete the optparse code in the next release - i.e. will you be able to port all applications to using the argparse decorators?

[kmvanbrunt]

No, we have plenty of time to port the old optparse code to argparse

[tleonhardt]

Re-targeting this for 0.8.5 since there was an emergency 0.8.4 release to alleviate a dependency issue in 0.8.3.

[tleonhardt]

On 2nd thought, this will go into the 0.9.0 release after support for Python 2.7 is abandoned.

There is no point in creating the potential headaches for end users involved with forcing them to port their old optparse decorator code to use the new argparse decorators when support for Python 2.7 is being abandoned anyways.