Removed add-on configurations

The new Spindle Class is a much better solution to
the problem that add-on's were intended to address.

builder.py

@@ -1,24 +1,20 @@
 # This script is imported by build-machine.py and build-all.py
-# It performs a platformio build with a given base machine file
-# and an optional add-on file.  The verbose argument controls
-# whether the full output is displayed, or filtered to show
-# only summary information.  extraArgs can be used to perform
-# uploading after compilation.
+# It performs a platformio build with a given machine file.
+# The verbose argument controls whether the full output is
+# displayed, or filtered to show only summary information.
+# extraArgs can be used to perform uploading after compilation.
 
 from __future__ import print_function
 import subprocess, os
 
 env = dict(os.environ)
 
-def buildMachine(baseName, addName=None, verbose=True, extraArgs=None):
+def buildMachine(baseName, verbose=True, extraArgs=None):
     cmd = ['platformio','run']
     if extraArgs:
         cmd.append(extraArgs)
     displayName = baseName
     flags = '-DMACHINE_FILENAME=' + baseName
-    if addName:
-        displayName += ' + ' + addName
-        flags += ' -DMACHINE_FILENAME2=' + addName
     print('Building machine ' + displayName)
     env['PLATFORMIO_BUILD_FLAGS'] = flags
     if verbose:
@@ -30,4 +26,4 @@ def buildMachine(baseName, addName=None, verbose=True, extraArgs=None):
                 print(line, end='')
     app.wait()
     print()
-    return app.returncode
+    return app.returncode