_scss: tweak white-space / margins

- Reduce white-space after headings, so that the section content groups
  better with the heading
- Increase white-space before headings, so that sections are more separated
  from the previous sections.
- Reduce indentation of bullet-lists and numbered-lists. These lists are
  still indented slightly (5px), but reducing the indentation to make the
  layout a bit less "busy", and to give list-items slightly more width
  before content is wrapped.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

_scss/_typography.scss

@@ -43,6 +43,8 @@ h1,h2,h3,h4,h5,h6 {
     font-family: $headings;
     clear: both;
     line-height: 26px;
+    margin-top:  30px;
+    margin-bottom: 0;
 }
 
 h1 {
@@ -75,3 +77,7 @@ h6 {
 dd, dt {
     line-height: 25px;
 }
+
+ol, ul {
+  padding-left: 25px;
+}