do not store error_list in check_fetched_value

error_list is set up in check_value. Handling of error and warnings are
now similar
test: fixed mandatory element and boolean
check_value is synchronous without a callback parameter

This allows simple check_value calls that are useful when
setting up default values.
change error_list attribute into errors attribute with Array trait
change warning_list attribute into warnings attribute with Array trait
factorize error checking
remove redundant test
fix store test
async test is all fixed for value.t