improved 'help' output

* sections separated by white space
* plugin names are nicely formatted, e.g `Plugin: Exception Explorer v0.1.9`

lib/pry/command.rb

@@ -140,7 +140,9 @@ class Pry
           when %r{/pry/.*_commands/(.*).rb}
             $1.capitalize.gsub(/_/, " ")
           when %r{/(pry-[^\/]*)/}
-            $1
+            $1 =~ /pry-([\w_]+)-([\d\.]+)/
+            name, version = $1, $2
+            "Plugin: #{name.capitalize.gsub(/_/, " ")} v#{version}"
           when /pryrc/
             "~/.pryrc"
           else

lib/pry/command_set.rb

@@ -363,7 +363,7 @@ class Pry
               end
 
               unless commands.empty?
-                help_text << "#{text.bold(key)}"
+                help_text << "\n#{text.bold(key)}"
                 help_text += commands.map do |command|
                   "  #{command.options[:listing].to_s.ljust(18)} #{command.description}"
                 end