Cleans up configuration system; Streams down dependencies

This MR solves the following issues:

• Cleans-up the configuration system so that it is both simpler and stores also the value of prefix
• Removes dependencies on colorlog (never useful anyway)

beat/cmdline/test/test_toolchains.py

@@ -31,7 +31,7 @@
 import os
 import nose.tools
 
-from . import platform, disconnected, prefix, tmp_prefix, user, token
+from . import platform, disconnected, prefix, tmp_prefix, user, token, temp_cwd
 from ..common import Selector, dot_diagram
 from ..scripts.beat import main
 from beat.core.test.utils import slow, cleanup, skipif
@@ -44,14 +44,15 @@ def call(*args, **kwargs):
   use_prefix = kwargs.get('prefix', prefix)
   use_platform = kwargs.get('platform', platform)
 
-  return main((
-      '--platform=%s' % use_platform,
-      '--user=%s' % user,
-      '--token=%s' % token,
-      '--prefix=%s' % use_prefix,
-      '--test-mode',
-      'toolchain',
-  ) + args)
+  with temp_cwd():
+    return main((
+        '--platform=%s' % use_platform,
+        '--user=%s' % user,
+        '--token=%s' % token,
+        '--prefix=%s' % use_prefix,
+        '--test-mode',
+        'toolchain',
+    ) + args)
 
 
 @slow