Remove three functions deprecated in 2015

We’ve had four years of console warnings, and this next release is known to be breaking.  Each is trivial to fix in code.

core/block.js

@@ -207,20 +207,6 @@ Blockly.Block = function(workspace, prototypeName, opt_id) {
   }
 };
 
-/**
- * Obtain a newly created block.
- * @param {!Blockly.Workspace} workspace The block's workspace.
- * @param {?string} prototypeName Name of the language object containing
- *     type-specific functions for this block.
- * @return {!Blockly.Block} The created block.
- * @deprecated December 2015
- */
-Blockly.Block.obtain = function(workspace, prototypeName) {
-  console.warn('Deprecated call to Blockly.Block.obtain, ' +
-               'use workspace.newBlock instead.');
-  return workspace.newBlock(prototypeName);
-};
-
 /**
  * Optional text data that round-trips beween blocks and XML.
  * Has no effect. May be used by 3rd parties for meta information.

core/blockly.js

@@ -377,21 +377,6 @@ Blockly.hideChaff = function(opt_allowToolbox) {
   }
 };
 
-/**
- * When something in Blockly's workspace changes, call a function.
- * @param {!Function} func Function to call.
- * @return {!Array.<!Array>} Opaque data that can be passed to
- *     removeChangeListener.
- * @deprecated April 2015
- */
-Blockly.addChangeListener = function(func) {
-  // Backwards compatibility from before there could be multiple workspaces.
-  console.warn(
-      'Deprecated call to Blockly.addChangeListener, ' +
-      'use workspace.addChangeListener instead.');
-  return Blockly.getMainWorkspace().addChangeListener(func);
-};
-
 /**
  * Returns the main workspace.  Returns the last used main workspace (based on
  * focus).  Try not to use this function, particularly if there are multiple

core/inject.js

@@ -528,14 +528,3 @@ Blockly.inject.loadSounds_ = function(pathToMedia, workspace) {
       Blockly.bindEventWithChecks_(document, 'touchstart', null, unbindSounds,
           true));
 };
-
-/**
- * Modify the block tree on the existing toolbox.
- * @param {Node|string} tree DOM tree of blocks, or text representation of same.
- * @deprecated April 2015
- */
-Blockly.updateToolbox = function(tree) {
-  console.warn('Deprecated call to Blockly.updateToolbox, ' +
-               'use workspace.updateToolbox instead.');
-  Blockly.getMainWorkspace().updateToolbox(tree);
-};