Remove redundant @dev tags (#995)

* Remove redundant @dev tags

* Remove redundant @notice tags

contracts/ECRecovery.sol

@@ -3,12 +3,9 @@ pragma solidity ^0.4.24;
 
 /**
  * @title Eliptic curve signature operations
- *
  * @dev Based on https://gist.github.com/axic/5b33912c6f61ae6fd96d6c4a47afde6d
- *
  * TODO Remove this library once solidity supports passing a signature to ecrecover.
  * See https://github.com/ethereum/solidity/issues/864
- *
  */
 
 library ECRecovery {
@@ -59,7 +56,7 @@ library ECRecovery {
   /**
    * toEthSignedMessageHash
    * @dev prefix a bytes32 value with "\x19Ethereum Signed Message:"
-   * @dev and hash the result
+   * and hash the result
    */
   function toEthSignedMessageHash(bytes32 hash)
     internal