use __POLIPO_BIND_PORT__ to avoid potential port conflict

fix ArgumentOutOfRangeException

prevent a bug

1. WrapTextTrigger -> wrapTextTrigger
2. WrapTextTriggerLock -> wrapTextTriggerLock
3. TopMostTrigger -> topMostTrigger
4. TopMostTriggerLock -> topMostTriggerLock
5. ShowToolbarTrigger -> toolbarTrigger

1. add menu items for `clear logs`, `change fonts`, `wrap text` and `top most` functions.
2. hide toolbar default. but you can trigger it out by menu.

follow with 5ae4df94e4

The stock code use class Random to generate IV, the Random is pseudo random number generator. The IV maybe repeat, this will cause shadowsocks-libev closed the sockets with the error message 'invalid password or cipher'. Reference https://github.com/shadowsocks/shadowsocks-libev/issues/389

Solution is use class RNGCryptoServiceProvider to generate IV, of course it's lower performance, but a little bit.

Sometimes the users may hit enter key by mistake, and the form will
close without saving entries.