||Deletes an existing index and removes it from the table
||DELINDEX(db : INTEGER; Index : INTEGER|STRING) : INTEGER
||db : table handle from OpenDB
Index: Index name (without path, but with extension) or index number
||0 = function successfully executed,
else error code
Most frequent error: "Index is still in use". While the index is the active access of a opened table, it can not be removed.
Attention: The mentioned index is deleted and removed from the table definitively. The function should be handled with care: Bacause tables can belong to more than one project, a project might not know from the necessity of an index in another project. After DelIndex all higher indices are decremented by 1.