pom.xml: version 2.0.0-SNAPSHOT + configure goal "mvn install" to install only smsuapi jar

(we don't want to publish the war, nor pom.xml)
do NOT purge "statistics" anymore (there is no reason to clean this table!)

on upgrade, you may need the following:

 delete from qrtz_cron_triggers where TRIGGER_NAME = 'purgeStatisticTrigger';
 delete from qrtz_triggers where JOB_NAME = 'purgeStatisticJob';
 delete from qrtz_job_details where JOB_CLASS_NAME = 'org.esupportail.smsuapi.services.scheduler.job.PurgeStatisticJob';
require java 7 (mostly to allow "switch" on strings)
pom.xml: remove commons-httpclient (replaced with plain HttpUrlConnection)
code cleanup: remove wrong comment
rename exception UnknownIdentifierApplicationException/UnknownIdentifierMessageException into AuthenticationFailed/UnknownMessageIdException
instead of returning a plain error string, return a json object { error: "xxx", message: "xxx" }
nicer WS errors in case invalid parameters
WIP migrate HttpUtils to HttpUrlConnection (instead of commons-httpclient)
WIP adapt to HttpUtils
WIP adapt HttpRequestSmsuapiWS to HttpUtils + enhance exceptions
HttpUtils: handle connect timeout (default timeout is 10s)
sendSms : return json objects with msg id + mayCreateAccountCheckQuotaOk : return json object

example of return value: { status: "OK", id: 123 }
cleanup: remove unused applicationService from actions
remove exceptionHandling + cleanup unused i18n/applicationService
cleanup build.xml: do not use ZIP archive anymore, rely on git/github
fix/update copyrights & links
web.xml: web-service answers on "/" instead of "/rest"
restore compatibility with java 6