ctp:ctpapi: update

1) log support is workable.
2) Add ContingentCondition for open_position().

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
ctp:ctpapi/ctpagent: add close position support

1) fix issue that can not close position.
2) chose OF_CloseToday as default flag to close positions.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
ctp:ctpagent/ctpapi/testctp: add cancel command

1) Add cancel_command().
2) Add test to cancel command.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>