Define types for methodID

packages/contracts/globals.d.ts

@@ -1,4 +1,3 @@
-declare module 'bn.js';
 declare module 'chai-bignumber';
 declare module 'dirty-chai';
 
@@ -31,6 +30,7 @@ declare module 'web3-eth-abi' {
 
 declare module 'ethereumjs-abi' {
     const soliditySHA3: (argTypes: string[], args: any[]) => Buffer;
+    const methodID: (name: string, types: string[]) => Buffer;
 }
 
 // Truffle injects the following into the global scope