Updated (shallower) project structure

Project Structure Changes:

• Remove resources/templates folder altogether
• Move posts and pages to content/ in root folder
• Move config.edn to content/ in root folder
• Move themes to root folder
• Move output folder public to root folder (specifiable via :public-dest)
• All user-specified resource paths are with respect to content/ folder (theme-specific resources will be relative to that theme's folder)

See cryogen-project/cryogen-core#117