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.

1. add `clean log` feature
2. add `change font` feature
3. add `wrap text` feature
4. add `top most` feature

2 fixes, 1 feature, 1 code beautify

1/ removed dual empty line
2/ removed tailing spaces
3/ converted tabs into spaces
4/ added some TODO comments

Update UpdateURL

Strategy: Simply Choose By Statistics

To add multiple servers in android phone, now it is no need to chose server one by one and generate QRCode for each. Just need to select the server listed in right.