Feat rc posts refactor

[RyanCCollins]

The proposed changes are as follows:

• Refactor posts into module to match hierarchy of routes
• Add post content blocks to the post home page without much styling (will come back later)
• Combine the post preview and match the mockups for post dashboard as best as possible
• Make reusable modules for error notification, loading indicator and others

Config

• Add flow-typed directory to .gitignore in favor setting up on install
• Tweak the flow settings
• Add missing babel-polyfill
• Tweak test settings