Lorm

[NEW] add ConnectionProxy.last_executed

[FIX] issue1 add backquote to field name. Thanks zhanghaofei.
[FIX] ignore unknown charset exception

[NEW] add "exclude" filter

[NEW] support transaction in autocommit mode.

[NEW] add transaction example

[NEW] rewrite connection-pool, now connection-pool is built-in.
cancel auto-reconnect.
cancel single connection mode, add Hub(), unified management connection pool.