Your mission is to make a key/value store.  It should implement the following features:
<ul>
<li>void store(String name, String value).  Stores the name in the database with the value.  If the name does not yet exist, create it.  If the name does exist, this is the replacement.
<li>String read(String name).  Returns the previous value associated with name.  If there is no such value, return the null string.
<li>void delete(String name).  Deletes the name/value pair if it exists.
<li>boolean exists(String name).  Returns true/false if the name is in the database.
</ul>

One point for each item.  Due thursday when we get back from break.