new function validateIdParam() in crud.utils.js reused in map.crud.js
new function validateData() in crud.utils.js reused in map.crud.js
refactored deletePoiCategory() in poi_category.crud.js
refactored validateData() and changed JSDocs in lib/utils.js
refactored poi_category.crud.js
refactored map.crud.js after changes in crud.utils.js
refactored poi_category.crud.js and added new function to utils.js: processPoiCategoriesCollection
added JSDocs
refactored poi.crud.js, poi.utils.js after changes in crud.utils.js