Remove peerDependencies

[Strate]

It is hard to use pre-release versions of mobx & mobx-react with this requirements.
See also npm/npm#8854 (comment)

[Strate]

@mweststrate what do you think about it? Can I merge?

[mweststrate]

Hmm not entirely sure about this one. It makes sure the minimum versions of the required api's are available. Violating peer deps is only a warning afaik in both npm 2 and 3 if you already provided the dependency yourself in the parent package? (which you should)

[Strate]

Unfortunatelly, that warning breaks shrinkwrap - shrinkwrap didn't write if unmet peer dependency.
Yet another one way to fix it - is to publish according version of this package, which includes pre-release version in peerDependency. Which is hard to maintain :(.

[mweststrate]

It is definitely annoying to use a pre release with these in place, but I think this is the correct thing to.

For now I just copy the folder contents manually when trying to test a fresh version