Updates demos to val keyword.

Updates demos to use `val` keyword instead of `const` (sarl/sarl#7).

src/main/sarl/io/sarl/demos/counter/counteragent.sarl

@@ -21,8 +21,8 @@ event Die {
 agent CounterAgent {
 	uses Lifecycle, Schedules, DefaultContextInteractions, Behaviors
 
-	const AtomicInteger count = new AtomicInteger
-
+	val AtomicInteger count = new AtomicInteger
+ 
 	on Initialize {
 		println("INITIALIZE: Start") 
 		task("test-presence").every(100) [ 

src/main/sarl/io/sarl/demos/filesearch/filesearch.sarl

@@ -50,12 +50,12 @@ agent FileSearchAgent {
 	}
 
 	on Search{
-		const minSize = e.minSize
+		val minSize = e.minSize
 
 		println(format("[ID=%s - parent %s] Searching in %s", ID, defaultContext.ID,myPath))
 
 
-		const File dir = new File(myPath)
+		val File dir = new File(myPath)
 		if(!dir.exists){
 			throw new IllegalArgumentException("Path ["+myPath+"] is not a Directory")
 		}

src/main/sarl/io/sarl/demos/websniffer/websniffer.sarl

@@ -17,7 +17,7 @@ event Count{
 agent Ticker{
 	uses DefaultContextInteractions, Schedules,Lifecycle
 
-	const AtomicInteger secs = new AtomicInteger
+	val AtomicInteger secs = new AtomicInteger
 
 	on Initialize {
 		every(100)[doCount]
@@ -28,8 +28,8 @@ agent Ticker{
 		emit(new Count => [count = secs.get])
 	}
 
-	def seconds(long val) : long{
-		val*1000
+	def seconds(long milis) : long{
+		milis*1000
 	}
 
 }