removed "trim" validator from README example since it does not exist
in validate_contains, added "isset" check to prevent a reference error
if a ruleset uses contains and that parameter is not provided
removed missing sanitization functions from the example
fixed a bug where you could not have a required field that accepts 0,
0.0, "0", or false due to the implementation of the empty function.
More can be read about what is considered "empty".  more can be read
about the empty function, here: http://us1.php.net/empty
Merge pull request #36 from mazubieta/master

Fixed: Example in documentation