Support CLI tools on Windows

The jsondiff and jsonpatch CLI tools do not work on Windows since they are installed as pre-written Linux scripts (i.e. extension-less and with a shebang) rather than being generated as a platform-specific console scripts upon installation.

Install the command line programs as console_scripts

thanks for your contribution, and sorry for the late response! a lot has changed in the repo, so I am preparing an updated implementation of your change in #231.