WIP cleanup: use standard spring RequestContextListener instead of home made context listener + esup-commons HttpUtils

all this is needed to access to ServletRequest inside ClientManager.java without passing it all the way
cleanup: remove unused serialVersionUID
code cleanup: remove unused attribute
code cleanup: add params to HashSet/ArrayList
web.xml: disable "servlet api 3.0 classpath scanning" otherwise dead slow startup
code cleanup: create helper method
do not wrongly urldecode twice parameters
test: add AckStatusSmsenvoi.get_arcode test
test: add OptionalTestSpringBeans to test spring beans
test: add testWriteJson for TrackInfos json serialization
replace Gson with jackson (rationale: jackson now used in smsu-api-admin)
replace json-simple with jackson (rationale: jackson now used in smsu-api-admin)

nb: json-simple requires junit directly. since we remove json-simple and need to require junit explictly
add WS action "MessageStatus" (needed for smsuapi proxy)
drop support for certificate authentication (not compatible with smsuapiadmin < 2.0)
add WS action "ActionMayCreateAccountCheckQuotaOk" (was available in XFire/SOAP but not available yet in simple WS)
smsuapi proxy: replace XFire with simple REST client