Amend tests and documentation for natural joins

These amendments are made in anticipation of the following library changes
(discussed in #66)

- Cross joins should not have any qualifiers
- Therefore natural cross joins should also not exist

index.html

@@ -162,7 +162,7 @@
       <li>- <a href="#join">join, leftJoin, rightJoin, fullJoin, crossJoin</a></li>
       <li>- <a href="#on">on</a></li>
       <li>- <a href="#using">using</a></li>
-      <li>- <a href="#join">naturalJoin, naturalLeftJoin, naturalRightJoin, naturalFullJoin, naturalCrossJoin</a></li>
+      <li>- <a href="#naturaljoin">naturalJoin, naturalLeftJoin, naturalRightJoin, naturalFullJoin</a></li>
       <li>- <a href="#selwhere">where</a></li>
       <li>- <a href="#groupBy">groupBy</a></li>
       <li>- <a href="#having">having</a></li>
@@ -361,6 +361,7 @@ <h2 id="select">select</h2>
         <span class="alias">Aliases: <b>innerJoin, leftOuterJoin, rightOuterJoin, fullOuterJoin</b></span>
         <br />
         <p>Adds the specified join to the query. <b>tbl</b> can include an alias after a space or after the <tt>'AS'</tt> keyword (<tt>'my_table my_alias'</tt>). <b>onCriteria</b> is optional if a <a href="#joinCriteria">joinCriteria</a> function has been supplied.</p>
+        <p><i>Note: <b>crossJoin</b> will ignore any <b>onCriteria</b> argument, if supplied.</i></p>
         <pre>
 select().from('person').join('address', {'person.addr_id': 'address.id'});
 // SELECT * FROM person INNER JOIN address ON person.addr_id = address.id
@@ -403,7 +404,7 @@ <h2 id="select">select</h2>
 </pre>
       </p>
       <p id="naturaljoin">
-        <b class="header">naturalJoin, naturalLeftJoin, naturalRightJoin, naturalFullJoin, naturalCrossJoin</b><br />
+        <b class="header">naturalJoin, naturalLeftJoin, naturalRightJoin, naturalFullJoin</b><br />
         <code>sel.naturalJoin(tbl)</code><br />
         <span class="alias">Aliases: <b>naturalInnerJoin, naturalLeftOuterJoin, naturalRightOuterJoin, naturalFullOuterJoin</b></span>
         <br />

tests/tests.js

@@ -509,7 +509,7 @@ describe('SQL Bricks', function() {
     it('.crossJoin() should generate a cross join', function() {
       check(select().from('usr').crossJoin('addr'),
         'SELECT * FROM "user" usr ' + 
-        'CROSS JOIN address addr ON usr.addr_fk = addr.pk');
+        'CROSS JOIN address addr');
     });
     it('join() should accept an expression for the on argument', function() {
       check(select().from('usr').join('addr', eq('usr.addr_id', sql('addr.id'))),
@@ -615,11 +615,6 @@ describe('SQL Bricks', function() {
         'SELECT * FROM "user" usr ' + 
         'NATURAL FULL JOIN address addr');
     });
-    it('.naturalCrossJoin() should generate a natural cross join', function() {
-      check(select().from('usr').naturalCrossJoin('addr'),
-        'SELECT * FROM "user" usr ' + 
-        'NATURAL CROSS JOIN address addr');
-    });
   });
 
   describe('WHERE clauses', function() {