Remove one or more strings from an array.
- Arguments
- prop: the array to remove the strings from (may be 0).
str : the string or string array to add.
- Result
- The given <prop> array without <str>.
The function just works on arrays created by _add_id().
This is an auxiliary function used in maintaining P_IDS, P_ADS,
P_CLASS_IDS and P_CLASS_ADS and should not be called by hand.