markdown, smackdown: add some internal links

this is not a proper wiki engine so we have to fix
some existing links ourselves

wiki/source/slrn.md

@@ -2,7 +2,7 @@
 title: slrn
 ---
 
-``slrn`` is a news reader for [[Usenet]].
+``slrn`` is a news reader for [Usenet](usenet-news.html).
 
 Documentation for slrn can be found at http://slrn.sourceforge.net 
 

wiki/source/tin.md

@@ -2,7 +2,7 @@
 title: tin
 ---
 
-tin is a threaded NNTP and spool based UseNet newsreader for a variety of platforms.
+tin is a threaded NNTP and spool based [UseNet](usenet-news.html) newsreader for a variety of platforms.
 
 http://www.tin.org/
 

wiki/source/tunnelblick.md

@@ -10,4 +10,4 @@ truckin.
 
 https://code.google.com/p/tunnelblick/
 
-To find a VPN endpoint, see the [[VPN Gate]] project.
+To find a VPN endpoint, see the [VPN Gate](vpn-gate.html) project.

wiki/source/usenet-news.md

@@ -7,7 +7,7 @@ title: usenet news
 We're working on it. You'll need a news server to read news, and it's up; 
 it's `news.tilde.club`.
 
-[[slrn]] is a newsreader; see http://slrn.sourceforge.net/ for details.
+[slrn](slrn.html) is a newsreader; see http://slrn.sourceforge.net/ for details.
 
 [[pine]] can read news; this
 [http://www.chebucto.ns.ca/Help/News/PineNews.html](tutorial) might help.
@@ -22,3 +22,4 @@ A for add, ^t for list
 
 [[lynx]] reads news, a la `lynx news://news.tilde.club/tilde.general`. It can even post news, but you have to design your own headers.
 
+There is also [tin](tin.html).

wiki/source/vpn-gate.md

@@ -8,5 +8,5 @@ designed with the Great Firewall of China in mind.
 
 http://www.vpngate.net/en/
 
-You may need client side software to make this work; [[tunnelblick]] is one
+You may need client side software to make this work; [tunnelblick](tunnelblick.html) is one
 such service on the Mac.