web: change header position from fixed to static

Mainly because anchors (`<a name=...>`) need to be offsetted to
account for the fixed header, and it ain't worth the hassle.

lib/GUI/css/styles.less

@@ -18,12 +18,7 @@
   padding: 0;
 
   .main-header {
-    position: fixed;
-    top: 0;
-    left: 0;
-    right: 0;
     background: @white;
-    z-index: 1;
 
     .navbar {
       margin-bottom: 0;
@@ -68,7 +63,7 @@
   }
 
   .content {
-    padding-top: @mainHeaderHeight + @packagesHeaderHeight + 10;
+    padding-top: 10px;
 
     .entry {
       .transition(height .3s);

lib/static/main.css

@@ -7233,12 +7233,7 @@ Original style from softwaremaniacs.org (c) Ivan Sagalaev <Maniac@SoftwareManiac
   padding: 0;
 }
 .body .main-header {
-  position: fixed;
-  top: 0;
-  left: 0;
-  right: 0;
   background: #ffffff;
-  z-index: 1;
 }
 .body .main-header .navbar {
   margin-bottom: 0;
@@ -7274,7 +7269,7 @@ Original style from softwaremaniacs.org (c) Ivan Sagalaev <Maniac@SoftwareManiac
   line-height: 1.7em;
 }
 .body .content {
-  padding-top: 120px;
+  padding-top: 10px;
 }
 .body .content .entry {
   -webkit-transition: height 0.3s;