implement first pass at update

[whyrusleeping]

This is a very early pass at automating the workflow of updating and bubbling up dependencies of a given package.

Usage:

1. in the directory of the root package you want to update the dep tree of, run gx-workspace update start PACKAGE
   • Where PACKAGE is the name of the package you want to update
2. run gx-workspace update next, it will update deps the first package in the todo list
3. Check the package to make sure it looks right, run tests, etc
4. run gx-workspace update next again, it will publish said package to ipfs and update the work state
5. repeat steps 2-4 until done

Notes:

• it only currently supports updating one 'base' package at a time, you can work around this by manually editing the gx-workspace-update.json file. This should get improved soon.
• It only works for go packages currently, will make it more general later
• It should respect your $GOPATH (if it doesnt, theres a bug)
  • this means you can set your gopath to a separate dir to cleanly sandbox things

[ghost]

Okay this is ready to go for now, since the basic operational method works.

What's next:

• Make git branch configurable and generate PRs (using hub?)
• Make the git-clone step part of the update preparation, instead of cloning within every package step
• Make the output nicer: be less verbose by default, and print every executed command's output in verbose mode
• Devide steps and phases better (--porcelain?)
• Have a meta command that does the whole process automatically