incremental data loading, flattened some sqltree types

packages/types/dialect.d.ts

@@ -1,5 +1,6 @@
 export interface SqlDialect {
   rangeSelect?: boolean;
   limitSelect?: boolean;
+  offsetFetchRangeSyntax?: boolean;
   quoteIdentifier(s: string): string;
 }

packages/types/dumper.d.ts

@@ -1,7 +1,9 @@
 import { TableInfo } from "./dbinfo";
+import { SqlDialect } from "./dialect";
 
 export interface SqlDumper {
   s: string;
+  dialect: SqlDialect;
 
   putRaw(s: string);
   put(format: string, ...args);