libncurses updated to v5.7

[Jan Lentfer]

I already posted this to users@ but didn't receive much responses so 
far. Mabye I have more luck on submit@:

I have updated contrib/ncurses and thus libncurses to version 5.7. On my 
local system this seems to work fine but since a lot of apps depend on 
it I'd like to see it tested more widely.

The relevant branches can be found here:

http://gitweb.dragonflybsd.org/~lentferj/dragonfly.git

ncurses_update & vendor/NCURSES.

Thanks for helping out!

Jan