Merge pull request #1 from leepike/master

Relaxed dependencies.
Separate library into separate directory
New tool to wrap markdown output formatter
Clean up Spreadsheet.Renderer
Factor sorting out of transform
Make format line properly optional

Previously there were issues with removing the format row
from a table with data in it and when removing it while
adding new rows with the '+' column token
gitignore: ignore cabal-dev.