[svn r55] Foreach was always generating code as if the value variable was 'ref'

Other not-so-major improvements

test/foreach5.d

@@ -0,0 +1,24 @@
+module foreach5;
+
+void main()
+{
+    int[3] arr = [1,2,3];
+
+    foreach(v;arr) {
+        v++;
+    }
+
+    printf("%d\n", arr[0]);
+    assert(arr[0] == 1);
+    assert(arr[1] == 2);
+    assert(arr[2] == 3);
+
+    foreach(ref v;arr) {
+        v++;
+    }
+
+    printf("%d\n", arr[0]);
+    assert(arr[0] == 2);
+    assert(arr[1] == 3);
+    assert(arr[2] == 4);
+}

test/foreach6.d

@@ -0,0 +1,15 @@
+module foreach6;
+
+struct S
+{
+    long l;
+    float f;
+}
+
+void main()
+{
+    S[4] arr;
+    foreach(i,v;arr) {
+        v = S(i,i*2.5);
+    }
+}