09a8148e36
This takes some of the machinery from CNI and from the rkt networking code, and turns it into a library that can be linked into go apps. Included is an example command-line application that uses the library, called `cnitool`. Other headline changes: * Plugin exec'ing is factored out The motivation here is to factor out the protocol for invoking plugins. To that end, a generalisation of the code from api.go and pkg/plugin/ipam.go goes into pkg/invoke/exec.go. * Move argument-handling and conf-loading into public API The fact that the arguments get turned into an environment for the plugin is incidental to the API; so, provide a way of supplying them as a struct or saying "just use the same arguments as I got" (the latter is for IPAM plugins).