rename register to risc

seems to fit the layer much better as we really have a very reduced
instruction set

test/risc/test_padding.rb

@@ -0,0 +1,20 @@
+require_relative "../helper"
+
+class TestPadding < MiniTest::Test
+
+  def test_small
+    [6,27,28].each do |p|
+      assert_equal 32 , Padding.padded(p) , "Expecting 32 for #{p}"
+    end
+  end
+  def test_medium
+    [29,33,40,57,60].each do |p|
+      assert_equal 64 , Padding.padded(p) , "Expecting 64 for #{p}"
+    end
+  end
+  def test_large
+    [61,65,88].each do |p|
+      assert_equal 96 , Padding.padded(p) , "Expecting 96 for #{p}"
+    end
+  end
+end