Update ERC721 to latest 1.11.0 from OpenZeppelin-solidity (#11)

* Update ERC721 to latest 1.11.0 from OpenZeppelin-solidity

* Hardcode supported interfaces instead of using lookup table. This avoids shifting storage when extending supports interface.

* Update build artifacts

* Fix linter errors

contracts/introspection/ERC165.sol

@@ -0,0 +1,20 @@
+pragma solidity ^0.4.21;
+
+
+/**
+ * @title ERC165
+ * @dev https://github.com/ethereum/EIPs/blob/master/EIPS/eip-165.md
+ */
+interface ERC165 {
+
+  /**
+   * @notice Query if a contract implements an interface
+   * @param _interfaceId The interface identifier, as specified in ERC-165
+   * @dev Interface identification is specified in ERC-165. This function
+   * uses less than 30,000 gas.
+   */
+  function supportsInterface(bytes4 _interfaceId)
+    external
+    view
+    returns (bool);
+}

contracts/introspection/ERC165Support.sol

@@ -0,0 +1,32 @@
+pragma solidity ^0.4.21;
+
+import "./ERC165.sol";
+
+/**
+ * @title ERC165Support
+ * @dev Implements ERC165 returning true for ERC165 interface identifier
+ */
+contract ERC165Support is ERC165 {
+
+  bytes4 internal constant InterfaceId_ERC165 = 0x01ffc9a7;
+  /**
+   * 0x01ffc9a7 ===
+   *   bytes4(keccak256('supportsInterface(bytes4)'))
+   */
+
+  function supportsInterface(bytes4 _interfaceId)
+    external
+    view
+    returns (bool) 
+  {
+    return _supportsInterface(_interfaceId);
+  }
+
+  function _supportsInterface(bytes4 _interfaceId)
+    internal
+    view
+    returns (bool) 
+  {
+    return _interfaceId == InterfaceId_ERC165;
+  }
+}