Send pad buffer to clients when they join; fixes issue 6524.
Allow user folder to be set via command line.

Clean up GetUserPath(), to allow setting any path with it.
Actually allow the dump and logs folders to be set outside of user/
Fix a crash in the Wiimote registration code

The code was hitting undefined behavior, causing crashes when starting a Wii
game with Dolphin compiled with gcc >= 4.8.

Might introduce some slight change in the Wiimote activation logic.

Fixes issue 6526.