Fix extensions to work under non-init_iruby environment

Author: domitry

lib/bionya/core.rb

@@ -1,4 +1,5 @@
 module Nyaplot
   add_extension("Bionya")
   add_additional_library("Bionya","https://rawgit.com/domitry/nyaplot/master/lib/bionya/js/release/bionya")
+  init_iruby if defined? IRuby
 end

lib/mapnya/core.rb

@@ -1,4 +1,5 @@
 module Nyaplot
   add_extension("Mapnya")
   add_additional_library("Mapnya","https://rawgit.com/domitry/nyaplot/master/lib/mapnya/js/release/mapnya")
+  init_iruby if defined? IRuby
 end

lib/nyaplot/core.rb

@@ -21,6 +21,11 @@ def self.add_dependency(name, url)
     @@dep_libraries[name]=url;
   end
 
+  # Load extension library to IRuby notebook before Nyaplotjs is loaded
+  def self.add_additional_library(name, url)
+    @@additional_libraries[name]=url
+  end
+
   # Enable to show plots on IRuby notebook
   def self.init_iruby
     path = File.expand_path("../templates/init.js.erb", __FILE__)

lib/nyaplot3d/core.rb

@@ -2,4 +2,5 @@ module Nyaplot
   add_extension("Elegans")
   add_dependency("THREE","http://cdnjs.cloudflare.com/ajax/libs/three.js/r66/three.min")
   add_dependency("Elegans","http://rawgit.com/domitry/elegans/nyaplot-extension/release/elegans")
+  init_iruby if defined? IRuby
 end