JavadocType doesn't report unused param tag
TestClass.java

```
package test;

/**
 * TestClass.
 * 
 * @param BAD
 *            This doesn't exist.
 */
public class TestClass {
    public void test() {
    }
}
```

config.xml

```
<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
          "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
          "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">

<module name="Checker">
    <property name="charset" value="ASCII" />
    <property name="severity" value="error" />
    <property name="fileExtensions" value="java" />

    <module name="TreeWalker">
        <module name="JavadocType">
            <property name="scope" value="public" />
        </module>
    </module>
</module>
```

output from: `java -jar checkstyle-6.14.1-all.jar -c config.xml TestClass.java`

```
Starting audit...
Audit done.
```

Expected output:

```
Starting audit...
[ERROR] D:\Rickys\Java\EclipseStuff\checkstyle\src\main\java\test\TestClass.java:6:4: Unused @param tag for 'BAD'. [JavadocType]
Audit done.
Checkstyle ends with 1 errors.
```

JavadocType should validate that if a param is defined, that it is used in the class definition so the 2 stay in synch. JavadocMethod will report unused params, so Type should follow suite.

Just as a note, class parameters are used by generic classes. (Ex: ArrayList&lt;T&gt;, T is considered the parameter)
