Transition to all camelCase key labels.

1. Hyphenated labels are still accepted when parsing scoped keys (so 'sbt test-only' still works)
   There is currently no timeline for removing this support for hyphenated keys.
2. Only camelCase is shown for tab completion.
3. AttributeKey.rawLabel provides the unnormalized label.
   This should only be used to implement support for accepting hyphenated keys as input for compatibility.
4. AttributeKey.normLabel provides the normalized label (hyphenated converted to camelCase)

util/collection/Attributes.scala

@@ -11,6 +11,8 @@ import scala.reflect.Manifest
 //  a single AttributeKey instance cannot conform to AttributeKey[T] for different Ts
 sealed trait AttributeKey[T] {
 	def manifest: Manifest[T]
+	@deprecated("Should only be used for compatibility during the transition from hyphenated labels to camelCase labels.", "0.13.0")
+	def rawLabel: String
 	def label: String
 	def description: Option[String]
 	def extend: Seq[AttributeKey[_]]
@@ -48,13 +50,15 @@ object AttributeKey
 
 	private[this] def make[T](name: String, description0: Option[String], extend0: Seq[AttributeKey[_]], rank0: Int)(implicit mf: Manifest[T]): AttributeKey[T] = new SharedAttributeKey[T] {
 		def manifest = mf
-		def label = name
+		def rawLabel = name
+		val label = Util.hyphenToCamel(name)
 		def description = description0
 		def extend = extend0
 		def rank = rank0
 	}
 	private[sbt] def local[T](implicit mf: Manifest[T]): AttributeKey[T] = new AttributeKey[T] {
 		def manifest = mf
+		def rawLabel = LocalLabel
 		def label = LocalLabel
 		def description = None
 		def extend = Nil

util/collection/Util.scala

@@ -26,8 +26,14 @@ object Util
 	def pairID[A,B] = (a: A, b: B) => (a,b)
 
 	private[this] lazy val Hypen = """-(\p{javaLowerCase})""".r
-	def hypenToCamel(s: String): String =
-		Hypen.replaceAllIn(s, _.group(1).toUpperCase)
+	def hasHyphen(s: String): Boolean = s.indexOf('-') >= 0
+	@deprecated("Use the properly spelled version: hyphenToCamel", "0.13.0")
+	def hypenToCamel(s: String): String = hyphenToCamel(s)
+	def hyphenToCamel(s: String): String =
+		if(hasHyphen(s))
+			Hypen.replaceAllIn(s, _.group(1).toUpperCase)
+		else
+			s
 
 	private[this] lazy val Camel = """(\p{javaLowerCase})(\p{javaUpperCase})""".r
 	def camelToHypen(s: String): String =