Remove OSX Panther instructions

Update dead rubyforge links

Fixes railsbridge#408

Author: tjgrathwell

assets/stylesheets/step.scss

@@ -76,19 +76,6 @@ img.noborder {
   padding-right: 20px;
 }
 
-.pertinent-info {
-  padding: 1em;
-  font-size: 0.8em;
-  font-color: rgb(60, 60, 60);
-  border: 3px solid grey;
-  border-radius: 10px;
-}
-
-.pertinent-info h3 {
-  text-align: center;
-  margin: 0;
-}
-
 .tip {
   padding: 1em;
   background-color: #F7FDFF;

sites/en/installfest/macintosh.step

@@ -33,9 +33,8 @@ step "Choose your instructions" do
   option "Yosemite/Mavericks/Mountain Lion/Lion/Snow Leopard" do
     link "osx_rvm"
   end
-  option "Leopard/Tiger/Panther" do
-    important "If at all possible, you should try upgrading to at least **Snow Leopard**. Apple doesn't sell it the Apple store anymore, so you'll have to [buy it from them online](http://store.apple.com/us/product/MC573Z/A/mac-os-x-106-snow-leopard) or find a copy from a friend."
-    message "Otherwise, you can try following the Panther instructions, but be prepared for some things to be difficult."
-    link "osx_panther"
+  option "Earlier than Snow Leopard" do
+    important "You should try upgrading to at least **Snow Leopard**. Apple doesn't sell it the Apple store anymore, so you'll have to [buy it from them online](http://store.apple.com/us/product/MC573Z/A/mac-os-x-106-snow-leopard) or find a copy from a friend."
+    message "It may be possible to get Ruby and Rails installed if your OS is older than Snow Leopard, but you're likely to encounter a lot of tough roadblocks that will require some intense googling."
   end
 end

sites/en/installfest/osx_panther.step

@@ -110,7 +110,7 @@ Special elements do *not* format their text as Markdown.
 
 ## erector elements
 
-StepFile is an [Erector](http://erector.rubyforge.org)-based DSL, so if you want to insert HTML tags or other stuff, use the appropriate Erector methods, e.g.
+StepFile is an [Erector](https://github.com/erector/erector)-based DSL, so if you want to insert HTML tags or other stuff, use the appropriate Erector methods, e.g.
 
     step "figure out your OS version" do
       message "Mac OS has code names, including:"