anchor.diff:  = Toporick
   
  -Toporick is an Ethereum Smart Contract for storing signatures of off-chain entities in blockchain. This
  -could be a signatures of digital documents, images, PDF or any other file.
  +Toporick is an Ethereum DApp for making agreements based on signatures of off-chain entities in the blockchain.
  +This can be signatures of digital documents, images, PDF or any other file.
   
   The plan is to make a collection of Smart Contracts, which will be helpful for making an agreement
   based on references to the off-chain digital documents.
   
   Roadmap:
   
  -  1. [X] publish signatures to blockchain - Simple Signature
  -  2. [ ] add signatures from multiple parties
  -  3. [ ] verification of signatures
  -  4. [ ] smart agreement based on state of signatures
  +  * [x] publish signatures to blockchain - Simple Signature
  +  * [ ] add signatures from multiple parties
  +  * [ ] publish UI
  +  * [ ] verification rules for a document
  +  ** [ ] timeframe
  +  ** [ ] same signatures from multiple parties
  +  ** [ ] required types of signatures
  +  * [ ] integrate into Mist
  +  * [ ] command line tools
   
   == Simple Signature contract
   
  
positive.code: 
  Use case:
  
   * to publish signatures of a downloadable file (like what we have for Ethereum client itself, published on
   official repo. Now it can also be published in blockchain)
   * signature of a correct file before making it public, as a proof of own/existence
  
  Notice that unlike to existing way of publishing such signatures on a website/ftp, publishing to blockchain through
     Toporick, protect signatures from forgery. Once it published on blockchain, it stays here forever.
  
  It allows to:
  
  
negative.code:  * only document author can add signatures to a document
  
  Notice that `type` and `value` could be anything, not restricted to any particular hash name or value.
    Which allows to store ordinary key-value pairs here. May be a metadata like "_filename=<filename in ascii>_".
  
  .Example 1, with standard signatures
  |=======================================================
  