Token metadata json schema (#1047)

* Add initial EIP skeleton

* Initial take through "Rationale"

* First very rough draft of ERC20 Metadata Extension

Nearly ready for comments by Matt, Matt, and John

* Initial "Token Metadata Standard" Proposal + small change to ERC721

- Added initial “Token Metadata JSON Schema”
- Re-named “ERC721 Metadata JSON Schema” to “Token Metadata JSON
Schema” in the ERC721 EIP

* ERC20 Metadata Extension ready to read

* Update Title of ERC Metadata Extension

* Fixing Matt's Github handle

Apparently Github handles for authors are meant to be “accurate” - who
knew?

* update grammatical errors; properly format JSON to remove excess commas

* update JSON descriptions & make grammatical changes to EIP

* Changed language in Token Metadata JSON Schema to reflect use by tokens which are not NFT's. Added clarification for backwards compatibility

* update authors and contact email

* Author Fix

* Removing ERC20 Metadata Extension

This branch is going to be just the Token Metadata Standard

* Removing change to 721 and renaming to 1047

* Full ERC721 revert

No changes to ERC721 in this PR

EIPS/eip-1047.md

@@ -0,0 +1,72 @@
+---
+eip: 1047
+title: Token Metadata JSON Schema
+author: Tommy Nicholas (@tomasienrbc), Matt Russo (@mateosu), John Zettler (@JohnZettler)
+discussions-to: https://www.reddit.com/r/raredigitalart/comments/8hfk2a/token_metadata_json_schema_eip_1047/
+status: Draft
+type: Standards Track
+category: ERC
+created: 2018-04-13
+---
+
+## Simple Summary
+A standard interface for token metadata
+
+## Abstract
+The ERC721 standard introduced the "tokenURI" parameter for non-fungible tokens to handle metadata such as:
+
+- thumbnail image
+- title
+- description
+- properties
+- etc.
+
+This is particularly critical for crypto-collectibles and gaming assets.
+
+This standard includes a reference to a metadata standard named "ERC721 Metadata JSON Schema". This schema is actually equally relevant to ERC20 tokens and therefore should be its own standard, separate from the ERC721 standard.
+
+## Motivation
+Metadata is critical for both ERC721 and ERC20 tokens representing things like crypto-collectibles, gaming assets, etc. Not all crypto-collectibles and gaming assets will be non-fungible. It is critical for fungible ERC20 tokens to have a metadata standard similar to that of ERC721 tokens. Standardization of metadata between ERC20 and ERC721 will simplify development of dApps and infrastructure that must support both fungible and non-fungible assets.
+
+It is more logical and easier to maintain one Token Metadata JSON Schema rather than multiple schemas contained in their own EIPs.
+
+This should result in no code changes to the ERC721 standard or ERC20 standard and will serve only to simplify the process of maintaining a standard JSON Schema for token metadata.
+
+## Specification
+
+This "Token Metadata JSON Schema" mimics the structure of the ERC721 standard. Only grammatical changes are being recommended at this time.
+
+```json
+{
+    "title": "Asset Metadata",
+    "type": "object",
+    "properties": {
+        "name": {
+            "type": "string",
+            "description": "Identifies the asset to which this token represents",
+        },
+        "description": {
+            "type": "string",
+            "description": "Describes the asset to which this token represents",
+        },
+        "image": {
+            "type": "string",
+            "description": "A URI pointing to a resource with mime type image/* representing the asset to which this token represents. Consider making any images at a width between 320 and 1080 pixels and aspect ratio between 1.91:1 and 4:5 inclusive.",
+        }
+    }
+}
+```
+## Rationale
+One JSON schema standard will allow for simpler maintenance of this critical schema.
+
+## Backwards Compatibility
+Fully backwards compatible requiring no code changes at this time
+
+## Test Cases
+TO-DO
+
+## Implementation
+TO-DO
+
+## Copyright
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).