Modernize SConstruct to make it Python 3 compatible

SConstruct

@@ -1,10 +1,12 @@
 # Setup
+from __future__ import absolute_import
+from __future__ import print_function
 import os
 env = Environment(ENV = os.environ)
 try:
     env.Tool('config', toolpath = [os.environ.get('CBANG_HOME')])
-except Exception, e:
-    raise Exception, 'CBANG_HOME not set?\n' + str(e)
+except Exception as e:
+    raise Exception('CBANG_HOME not set?\n' + str(e))
 
 env.CBLoadTools('packager run_distutils osx fah-client-version')
 env.CBAddVariables(
@@ -14,7 +16,7 @@ conf = env.CBConfigure()
 # Version
 try:
     version = env.FAHClientVersion()
-except Exception, e:
+except Exception as e:
     print(e)
     version = '0.0.0'
     env.Replace(PACKAGE_VERSION = version)