Plugin wrapper for daemon version of various go tools

[myitcv]

First need to write a daemon version of the tool (likely will expose an RFC interface). Then write a plugin that essentially provides the Neovim interaction to the tool, i.e. RFC <-> MSGPACK

• goimports
• gocode
• go oracle

Tools that don't need daemon wrappers will be handled separately. But should be written to share a generated AST (instead of each running as a separate process and each parsing to an AST).