No one uses this, and it is causing confusion (see #150)
The executable command-line API uses the type of network (see [Network Configuration](#network-configuration) below) as the name of the executable to invoke.
It will then look for this executable in a list of predefined directories. Once found, it will invoke the executable using the following environment variables for argument passing:
-- `CNI_VERSION`: [Semantic Version 2.0](http://semver.org) of CNI specification. This effectively versions the CNI_XXX environment variables.
- `CNI_COMMAND`: indicates the desired operation; either `ADD` or `DEL`
- `CNI_CONTAINERID`: Container ID
- `CNI_NETNS`: Path to network namespace file