If a table column name begins with "__hidden__" then do not include that

column in "*" expansions in SELECT statements, nor fill in that column in
an INSERT INTO that omits the column list.  <b>This branch is a 
proof-of-concept only and is not intended to ever be merged into trunk.</b>

FossilOrigin-Name: 2dbffb3a3b20dba7d7d86c8ad2e34633f616c78a

src/select.c

@@ -4365,7 +4365,8 @@ static int selectExpander(Walker *pWalker, Select *p){
             ** result-set list.
             */
             if( IsHiddenColumn(&pTab->aCol[j]) ){
-              assert(IsVirtual(pTab));
+              assert( IsVirtual(pTab)
+               || sqlite3_strnicmp(pTab->aCol[j].zName,"__hidden__", 10)==0 );
               continue;
             }
             tableSeen = 1;