The keys of the config are not handled the same in the class. Everywhere lowercased keys are used except at hasOption($key).

Problem code:

    /**
     * Is an option present?
     * 
     * @param  string $key 
     * @return bool
     */
    public function hasOption($key)
    {
        return in_array($key, $this->_optionKeys);
    }

Suggested fix:

    /**
     * Is an option present?
     * 
     * @param  string $key 
     * @return bool
     */
    public function hasOption($key)
    {
        return in_array(strtolower($key), $this->_optionKeys);
    }