Change to https for tigervnc URL

Our main web site now supports https, so update all references.
diff --git a/unix/vncconfig/vncconfig.man b/unix/vncconfig/vncconfig.man
index 06f9ca9..b685a46 100644
--- a/unix/vncconfig/vncconfig.man
+++ b/unix/vncconfig/vncconfig.man
@@ -114,7 +114,7 @@
 .BR vncserver (1),
 .BR Xvnc (1)
 .br
-http://www.tigervnc.org
+https://www.tigervnc.org
 
 .SH AUTHOR
 Tristan Richardson, RealVNC Ltd. and others.
diff --git a/unix/vncpasswd/vncpasswd.man b/unix/vncpasswd/vncpasswd.man
index a62c0ed..9e68181 100644
--- a/unix/vncpasswd/vncpasswd.man
+++ b/unix/vncpasswd/vncpasswd.man
@@ -47,7 +47,7 @@
 .BR Xvnc (1)
 .BR vncconfig (1),
 .br
-http://www.tigervnc.org
+https://www.tigervnc.org
 
 .SH AUTHORS
 Tristan Richardson, RealVNC Ltd., Antoine Martin, D. R. Commander and others.
diff --git a/unix/vncserver.man b/unix/vncserver.man
index 9108683..95f7960 100644
--- a/unix/vncserver.man
+++ b/unix/vncserver.man
@@ -192,7 +192,7 @@
 .BR vncconfig (1),
 .BR Xvnc (1)
 .br
-http://www.tigervnc.org
+https://www.tigervnc.org
 
 .SH AUTHOR
 Tristan Richardson, RealVNC Ltd., D. R. Commander and others.
diff --git a/unix/x0vncserver/x0vncserver.man b/unix/x0vncserver/x0vncserver.man
index 5dc0b05..5f1508c 100644
--- a/unix/x0vncserver/x0vncserver.man
+++ b/unix/x0vncserver/x0vncserver.man
@@ -302,7 +302,7 @@
 .BR Xvnc (1),
 .BR vncpasswd (1),
 .br
-http://www.tigervnc.org/
+https://www.tigervnc.org/
 
 .SH AUTHOR
 Constantin Kaplinsky and others.
diff --git a/unix/xserver/hw/vnc/Xvnc.man b/unix/xserver/hw/vnc/Xvnc.man
index 269be9a..224aeba 100644
--- a/unix/xserver/hw/vnc/Xvnc.man
+++ b/unix/xserver/hw/vnc/Xvnc.man
@@ -396,7 +396,7 @@
 .BR Xserver (1),
 .BR inetd (1)
 .br
-http://www.tigervnc.org
+https://www.tigervnc.org
 
 .SH AUTHOR
 Tristan Richardson, RealVNC Ltd. and others.
diff --git a/unix/xserver/hw/vnc/xvnc.c b/unix/xserver/hw/vnc/xvnc.c
index 3b4d2f3..79b0e3d 100644
--- a/unix/xserver/hw/vnc/xvnc.c
+++ b/unix/xserver/hw/vnc/xvnc.c
@@ -89,7 +89,7 @@
 
 #define XVNCVERSION "TigerVNC 1.9.80"
 #define XVNCCOPYRIGHT ("Copyright (C) 1999-2018 TigerVNC Team and many others (see README.rst)\n" \
-                       "See http://www.tigervnc.org for information on TigerVNC.\n")
+                       "See https://www.tigervnc.org for information on TigerVNC.\n")
 
 #define VFB_DEFAULT_WIDTH  1024
 #define VFB_DEFAULT_HEIGHT 768