New procedures added to win/win32/vs2017/travisci.sh for travis-ci testing.
- use curl to obtain Lua from http://www.lua.org/ftp/lua-5.3.5.tar.gz
- use tar to unzip lua into lib/lua-5.3.5/...
Note: curl and tar were both added as part of Windows 10 in late Dec 2017
https://techcommunity.microsoft.com/t5/Containers/Tar-and-Curl-Come-to-Windows/ba-p/382409
- use git to clone pdcurses into lib/pdcurses
- use git to clone universal-ctags into lib/ctags
- build universal-ctags ahead of building NetHack + lua + pdcurses
- adjust sys/winnt/Makefile.msc to look for those things in their lib locations when
building under travis