Add man page.

Proposed PR adds man page to the project. To review the page without installation you can use next command. ``` $ mandoc microsocks.1 | less ``` @rofl0r, also I noticed that usage info printed by `microsocks -h` is not full and messy. What do you think if I propose one more PR to align it to make it looks more traditional (like in other commands)? I'm thinking something about: ``` usage: microsocks [-1q] [-b ip] [-i addr] [-P pass] [-p port] [-u user] [-w ips] -1 activates auth_once mode -b ip IP to bind outgoing connections to -i addr local address to listen to ... ```