Added enable_all_gpus.py

This script was written by @brecht to enable all GPUs/CPUs in T54099.

flamenco_worker/blendscripts/enable_all_gpus.py

+# ##### BEGIN GPL LICENSE BLOCK #####
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ##### END GPL LICENSE BLOCK #####
+
+# <pep8 compliant>
+import bpy
+
+scene = bpy.context.scene
+scene.cycles.device = 'GPU'
+
+prefs = bpy.context.user_preferences
+cprefs = prefs.addons['cycles'].preferences
+
+# Attempt to set GPU device types if available
+for compute_device_type in ('CUDA', 'OPENCL', 'NONE'):
+    try:
+        cprefs.compute_device_type = compute_device_type
+        break
+    except TypeError:
+        pass
+
+# Enable all CPU and GPU devices
+for device in cprefs.devices:
+    device.use = True