Move the output_store to a file_store file under output_stores
Changed the class from OutputStore to OutputStores::FileStore
Add FileReader

Split out reader so that it can injected at runtime based on what type
of reader should handle the reading of files
Use FileReader for the markdown renderer

Implemented this for now until it is injected
Stubbed dropbox get file

Reads contents from a temporary file and returns that from the fake api
Create dropbox_reader for reading dropbox files