cleanup; remove warnings

update demo location

completed circle drawer

link to live demo; some style changes

use fixed listWithKeyShallowDiff

some sheet styling

refactoring and renaming

use decimal; better structured cell results

rebased on master

moved graph logic to new module References

ghc7.10.3

fix fromVertex

didn't check: removed getSCCs in favor of hasCycles (#1)

first spreadsheet version

sheet monad