Merge recent trunk enhancements, including the read-after-ROLLBACK change

and the addition of sqlite3_stmt_scanstatus() support, as well as various
minor bug fixes.

FossilOrigin-Name: f09055f3c4348264c7336f90646375f0d98b061e

src/vdbeblob.c

@@ -380,7 +380,6 @@ static int blobReadWrite(
   if( n<0 || iOffset<0 || (iOffset+n)>p->nByte ){
     /* Request is out of range. Return a transient error. */
     rc = SQLITE_ERROR;
-    sqlite3Error(db, SQLITE_ERROR);
   }else if( v==0 ){
     /* If there is no statement handle, then the blob-handle has
     ** already been invalidated. Return SQLITE_ABORT in this case.
@@ -422,10 +421,10 @@ static int blobReadWrite(
       sqlite3VdbeFinalize(v);
       p->pStmt = 0;
     }else{
-      db->errCode = rc;
       v->rc = rc;
     }
   }
+  sqlite3Error(db, rc);
   rc = sqlite3ApiExit(db, rc);
   sqlite3_mutex_leave(db->mutex);
   return rc;