Revert "Merge pull request #379 from pipex/latex-dollar-sign"

This reverts commit b53c961db2, reversing
changes made to 9c40cbea76.

lib/gollum/markup.rb

@@ -124,30 +124,17 @@ module Gollum
     #
     # Returns the placeholder'd String data.
     def extract_tex(data)
-      # Random string to escape the `$` character (might be overkill)
-      esc = "/%%/"
       data.gsub(/\\\[\s*(.*?)\s*\\\]/m) do
         tag = CGI.escapeHTML($1)
         id  = Digest::SHA1.hexdigest(tag)
         @texmap[id] = [:block, tag]
         id
-      end.gsub(/'\$/, esc). # Replace `'$` with the `esc` string in order to escape it
-        gsub(/\$\$\s*(.*?)\s*\$\$/m) do
-          tag = CGI.escapeHTML($1)
-          id  = Digest::SHA1.hexdigest(tag)
-          @texmap[id] = [:block, tag]
-          id
       end.gsub(/\\\(\s*(.*?)\s*\\\)/m) do
         tag = CGI.escapeHTML($1)
         id  = Digest::SHA1.hexdigest(tag)
         @texmap[id] = [:inline, tag]
         id
-      end.gsub(/\$\s*(.*?)\s*\$/m) do # match inline $<formula>$ 
-        tag = CGI.escapeHTML($1)
-        id  = Digest::SHA1.hexdigest(tag)
-        @texmap[id] = [:inline, tag]
-        id
-      end.gsub(/#{esc}/, '$') # replace the `esc` string back to `$`
+      end
     end
 
     # Process all TeX from the texmap and replace the placeholders with the