Update ST.java

[JackLovel]

I run this java file in win10 windows console , but I can't stop input;
so I add this code if(key.equals("q")) break; that can stop input and output result;

[JackLovel]

When I run BinarySearchST.java in win10 console , happen a Uncheck problem.

• Translated into English

  BinarySearchST.java:82: Warning: [unchecked] unchecked conversion 
      keys = (Key[]) new Comparable[capacity];
                     ^
  need: Key[]
  find:    Comparable[]
  Key is a type variable:
  The Key extension has declared Comparable < Key > in the class BinarySearchST
  BinarySearchST.java:83: Warning: [unchecked] unchecked conversion 
      vals = (Value[]) new Object[capacity];
                       ^
  need: Value[]
  find:    Object[]
  Value is a type variable:
  Value extends Object declared in the class BinarySearchST 
  BinarySearchST.java:90: Warning: [unchecked] unchecked conversion 
      Key[]   tempk = (Key[])   new Comparable[capacity];
                                ^
  need: Key[]
  find:    Comparable[]
  Key is a type variable
  The Key extension has declared Comparable < Key > in the class BinarySearchST 
  BinarySearchST.java:91: Warning: [unchecked] unchecked conversion 
      Value[] tempv = (Value[]) new Object[capacity];
                                ^
  need: Value[]
  find:    Object[]
  Value is a type variable:
  Value extends Object declared in the class BinarySearchST
  4 warnings 

• Solutions

Added @SuppressWarnings("unchecked") before the following two functions:

public BinarySearchST(int capacity) {...}

private void resize(int capacity) {...}