StatFunctions

New function for expression manager to count some statistics data :

• statCount(QuestionCode.sgqa[, submitted = true]) : count the answered question of QuestionCode already submitted. You can count the submitted survey with statCount('sid') for example.
• statCountIf(QuestionCode.sgqa, value[, submitted = true]) : count the response where answer to question QuestionCode are value.

You can find an usage of this 2 functions in survey_archive_statCountFunctionsTest inside test directory.