2.10.0-M5, different arity generalization

1. KList[M[_]] now instead of KList[HL <: HList, M[_]]
  a. head, tail work properly in this variant
  b. disadvantage is that full type not easily transformed to new type constructor
2. AList abstracts on K[L[x]], a higher order type constructor.
 A. Instances written for:
  a. KList
  b. Seq[M[T]] for a fixed T
  c. TupleN
  d. single values
  e. operate on one type constructor when nested
 B. Main disadvantage is type inference.  It just doesn't happen for K[L[x]].
    This is mitigated by AList being used internally and rarely needing to construct a K.

scripted/plugin/ScriptedPlugin.scala

@@ -3,7 +3,7 @@
  */
 package sbt
 
-import Project.Initialize
+import Def.Initialize
 import Keys._
 import classpath.ClasspathUtilities
 import java.lang.reflect.Method