Decouple coderack: remove global variable coderack.

Or at least, hide it upstairs in `copycat.py`.
`copycat.py` will eventually become a class, I'm guessing,
but let's pull everything into it first.

copycat/coderack.py

@@ -21,7 +21,7 @@ def getUrgencyBin(urgency):
     return i + 1
 
 
-class CodeRack(object):
+class Coderack(object):
     def __init__(self):
         self.pressures = CoderackPressures()
         self.pressures.initialisePressures()
@@ -288,6 +288,3 @@ class CodeRack(object):
             method(self, codelet)
         except AssertionError:
             pass
-
-
-coderack = CodeRack()

copycat/copycat.py

@@ -3,8 +3,9 @@ import logging
 from workspace import workspace
 from slipnet import slipnet
 from temperature import temperature
-from coderack import coderack
+from coderack import Coderack
 
+coderack = Coderack()
 
 def updateEverything():
     workspace.updateEverything()