New skeleton with modules.

No real code yet.
Added Types, Render code from old version.
Progress on container parsing.
Fleshed out basics of container parsing.
Modified slogan.
Simplified stack code
Improved types to make errors impossible
Supported Rule
Added .ghci
Fixed bugs, added custom Show for Container
Renamed Cheapskate.Blocks -> Cheapskate.Parse.

We'll also include inline parsing in this module.
Renamed Blocks -> Parse.
TextLines -> TextLine.
Added more Leaf/Container types
Add line number for every leaf
Setext headers working.
Added container type for fenced code blocks.
Implemented fenced code blocks.
Added ListItem container.
List items.