added two useful properties/flags to "CamelCapsFunctionNameSniff.php"

These flags can be used to get out of trouble when standards conflict a bit like in the following case:

- private methods must be prefixed with an underscore (_fooBar())
- methods must have CamelCaps-Format (fooBar()) [but private are allowed as an exception]

i decided to implement these flags/properties in "CamelCapsFunctionNameSniff.php" cause it's a wide spread standard to prefix private methods and properties with an underscore.

<!-- NamingConventions -->
<rule ref='Generic.NamingConventions.CamelCapsFunctionName'>
    <properties>
        <property name='excludePrivateMethods' value='false'/>
        <property name='removeUnderscoreFromMethod' value='true'/>
    </properties>
</rule>"