mapfishapp-upload geofile- improve the memory handle related with the feature collection response.

The following error was thrown building the string to set the response. 

2013-09-24 15:41:33 DispatcherServlet [DEBUG] Could not complete request
org.springframework.web.util.NestedServletException: Handler processing failed; nested exception is java.lang.OutOfMemoryError: Java heap space

It is necessary to improve in order to manage bigger json string. In this improvement the json features are written in the response object when they are extracted from the collection. 

Additionally, it is included the MaxInMemorySize property  in the CommonsMultipartResolver, thus the upload file manager can check the memory limits 

<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="MaxInMemorySize">
            <!--  default value 10240 bytes -->
            <value>10240</value> 
        </property>
</bean>