Make icon compatible with WinXP

The icon failed to render under WinXP both
as an application icon in explorer and as a tray icon.
Just opened and saved it again in GIMP and that fixed it.
Don't know what exactly was wrong, the only difference
I noticed is 256 -> 16 color depth change. But since
the image consists just of the black color of varying
transparency, I think it's fine.
Change tray icon until focused

This is to make having unread messages more apparent,
especially when the window is minimized to tray.

I whipped up a new acid-trip-like easy-to-notice icon
for that purpose, due to the lack of an official
tray notification icon mockups. Feel free to change it.
Czech language
Switched save directory on windows to real appdata instead of local.

Added code to load everything from the old directory.
Merge branch 'master' of https://github.com/Zeeno-atl/uTox

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Added LANG_CS to language enum.
Draw friend request message in friend request window.

TODO: There's a lot of empty space on that window that could be used to draw the message instead of drawing it like a friend status message.
Fixed crash.
Merge branch 'tray_icon_unread' of https://github.com/albel727/uTox

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Merge branch 'winxp_icon_fix' of https://github.com/albel727/uTox
uTox is at version 0.1.8
Added MAX_NUM_FRIENDS define.

TODO: Dynamic arrays so number of friends isn't limited to 256.