add implemented algorithms in doc (#142)

docs/_static/build_toc_group.js

+// modified from
+// https://stackoverflow.com/questions/12150491/toc-list-with-all-classes-generated-by-automodule-in-sphinx-docs
+
+$(function (){
+  var createList = function(selected) {
+    var obj = {};
+    var ul = $('<ul>');
+
+    selected.each(function(i,e) {
+
+      var groupName = $(e).find('a')[0].href;
+      groupName = groupName.substr(groupName.lastIndexOf('/')+1);
+      groupName = groupName.substr(0,groupName.lastIndexOf(".html"));
+      
+
+      var fullname = e.id;
+      if (fullname.startsWith('parl.'))
+        index = fullname.lastIndexOf('.')
+        fullname = "parl.algorithms.".concat(fullname.substr(index+1))
+
+      if (fullname == "dataflow.MultiProcessMapData") {
+        groupName = "parallel_map";
+      }
+
+      var n = $(e).children('.descname').clone();
+      n[0].innerText = fullname;
+
+      var l = $(e).children('.headerlink');
+      var a = $('<a>');
+      a.attr('href', l.attr('href')).attr('title', 'Link to this definition');
+      a.append(n);
+
+      var entry = $('<li>').append(a);
+
+      if(groupName in obj) {
+        obj[groupName].append(entry);
+      } else {
+        var ul = $('<ul style="margin-bottom: 12px;">');
+        ul.append(entry);
+        obj[groupName] = ul;
+      }
+    });
+
+    return obj;
+  }
+
+
+
+  var customIndex = $('.custom-index');
+  customIndex.empty();
+
+
+  var selected = $('div.section>dl>dt');
+  if (selected.length === 0)
+    return;
+
+  var obj = createList(selected);
+  var block = $('<div style="min-width: 300px; margin-bottom: 2em;">');
+  for(var key in obj) {
+    var a = $('<h6 style="margin-bottom: 0;">');
+    a.html(key + ':');
+    block.append(a);
+    block.append(obj[key]);
+  }
+  customIndex.append(block);
+});

docs/implementations.rst

 Implemented Algorithms
 ========================
+
+.. container:: custom-index
+
+    .. raw:: html
+
+        <script type="text/javascript" src='../_static/build_toc_group.js'></script>
+
+.. automodule:: parl.algorithms.fluid.impala.impala
+    :members:
+    :no-undoc-members:
+    :show-inheritance:
+
+.. automodule:: parl.algorithms.fluid.a3c
+    :members:
+    :no-undoc-members:
+    :show-inheritance:
+
+.. automodule:: parl.algorithms.fluid.ddpg
+    :members:
+    :no-undoc-members:
+    :show-inheritance:
+
+.. automodule:: parl.algorithms.fluid.dqn
+    :members:
+    :no-undoc-members:
+    :show-inheritance:
+
+.. automodule:: parl.algorithms.fluid.policy_gradient
+    :members:
+    :no-undoc-members:
+    :show-inheritance:
+
+.. automodule:: parl.algorithms.fluid.ppo
+    :members:
+    :no-undoc-members:
+    :show-inheritance: