Add Roadmap

[sungwoncho]

Add roadmap with short-term and long-term goals of the project

[macrozone]

maybe we do something like https://github.com/meteor/meteor/blob/devel/Roadmap.md

but i think a section in the readme would be enough to start with

[StorytellerCZ]

So what are those goals?

I think #110 and similar should be included in short term goals. Long term goals can be a bit more ambiguous.

Apollo integration should be probably added as well, since it doesn't look like we won't have official integration for a bit, but there are some resources we can tap into: http://dev.apollodata.com/core/#Meteor-Examples

Other features that come to mind: #85 React Native support #86 Redux #90 Rename functionality