converted if() throw convention to require()/assert()/revert()

contracts/payment/PullPayment.sol

@@ -32,19 +32,12 @@ contract PullPayment {
     address payee = msg.sender;
     uint256 payment = payments[payee];
 
-    if (payment == 0) {
-      throw;
-    }
-
-    if (this.balance < payment) {
-      throw;
-    }
+    require(payment != 0);
+    require(this.balance >= payment);
 
     totalPayments = totalPayments.sub(payment);
     payments[payee] = 0;
 
-    if (!payee.send(payment)) {
-      throw;
-    }
+    assert(payee.send(payment));
   }
 }