Add some missing wrappers (#1139)

* Add some missing wrappers:

sqlite3_value_subtype
sqlite3_result_subtype
sqlite3_changes64
sqlite3_db_readonly
sqlite3_txn_state
sqlite3_stmt_isexplain
sqlite3_vtab_config
sqlite3_index_info.idxFlags
sqlite3_index_info.colUsed
sqlite3_index_info.idxStr
sqlite3_vtab_collation

* Mark series VTab as innocuous and csv as direct only

src/trace.rs

@@ -119,6 +119,8 @@ impl Connection {
             None => unsafe { ffi::sqlite3_profile(c.db(), None, ptr::null_mut()) },
         };
     }
+
+    // TODO sqlite3_trace_v2 (https://sqlite.org/c3ref/trace_v2.html) // 3.14.0, #977
 }
 
 #[cfg(test)]