Update plugin framework to distinguish between viz and IE frameworks.

Update IPython accordingly.

config/plugins/interactive_environments/ipython/config/ipython.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE visualization SYSTEM "../../interactive_environments.dtd">
-<visualization name="IPython">
+<!DOCTYPE interactive_environment SYSTEM "../../interactive_environments.dtd">
+<interactive_environment name="IPython">
     <data_sources>
         <data_source>
             <model_class>HistoryDatasetAssociation</model_class>
@@ -13,4 +13,4 @@
         <param type="dataset" var_name_in_template="hda" required="true">dataset_id</param>
     </params>
     <template>ipython.mako</template>
-</visualization>
+</interactive_environment>

config/plugins/visualizations/visualization.dtd

@@ -1,5 +1,6 @@
 <!-- each visualization must have a template (all other elements are optional) -->
 <!ELEMENT visualization (description*,data_sources*,params*,template_root*,template,render_target*)>
+<!ELEMENT interactive_environment (description*,data_sources*,params*,template_root*,template,render_target*)>
 <!-- visualization
         name: the title/display name of the visualization (e.g. 'Trackster', 'Fastq Stats', etc.) REQUIRED
         disabled: if included (value does not matter), this attribute will prevent the visualization being loaded

lib/galaxy/visualization/registry.py

@@ -401,6 +401,10 @@ class VisualizationsConfigParser( object ):
         """
         returned = {}
 
+        # main tag specifies plugin type (visualization or
+        # interactive_enviornment).
+        returned[ 'plugin_type' ] = xml_tree.tag
+
         # a text display name for end user links
         returned[ 'name' ] = xml_tree.attrib.get( 'name', None )
         if not returned[ 'name' ]: