Refactor folders in preparation for external audit

Fix typos

On unrelated note, why on earth check like in safeAdd? Is it actually an overflow check?

Add tag comment on CONTRIBUTING.md

Fixes #116

DelayedClaimable contract extension of Claimable fix #64

Decouple Shareable from DayLimit

Create tests for MultisigWallet

fix link

add introductory guide to smart contracts

Add payable modifier to bid functions in examples

Create tests for Shareable

Create tests for DayLimit

add 2 lines between top level definitions

update readme

Documentation

resolve conflict between Ownable and ERC20 token.