Fix MaxCPU and MaxMemory semantics

If a limit of 0 (or negative) is given for both cpu and memory, then
no limiting will be triggered. If any value between 1 and 100 (inclusive)
is given, then limiting will be triggered when that limit is reached.

I.e. giving a limit of 100 doesn't not mean unlimited.

resources/resources_test.go

@@ -177,6 +177,16 @@ func TestHasLimits(t *testing.T) {
 
 	require.True(t, r.HasLimits())
 
+	r, err = New(Config{
+		MaxCPU:    100,
+		MaxMemory: 100,
+		PSUtil:    &util{},
+		Logger:    nil,
+	})
+	require.NoError(t, err)
+
+	require.True(t, r.HasLimits())
+
 	r, err = New(Config{
 		MaxCPU:    0,
 		MaxMemory: 0,