reorganize examples into folder

contracts/BadArrayUse.sol → contracts/examples/BadArrayUse.sol

@@ -1,4 +1,4 @@
-import './PullPaymentCapable.sol';
+import '../PullPaymentCapable.sol';
 
 // UNSAFE CODE, DO NOT USE!
 

contracts/GoodArrayUse.sol → contracts/examples/GoodArrayUse.sol

@@ -1,4 +1,4 @@
-import './PullPaymentCapable.sol';
+import '../PullPaymentCapable.sol';
 
 contract GoodArrayUse is PullPaymentCapable {
   address[] employees;

contracts/PullPaymentBid.sol → contracts/examples/PullPaymentBid.sol

@@ -1,4 +1,4 @@
-import './PullPaymentCapable.sol';
+import '../PullPaymentCapable.sol';
 
 contract PullPaymentBid is PullPaymentCapable {
   address public highestBidder;