Fixes bug 884125 partially

 * Adding a minimum width prevents the buttons from cutting off the text on them.
 * The problem with the title is not fixable with qss styling

SLE/wizard/installation.qss

@@ -6,24 +6,21 @@ YQWizard { background: #2d2d2d; }
 
 #LogoHBox {
   border-image: url(header-background.png);
-  padding: none;
-  border: none;
   background-color: #000;
 }
 #DialogLogo {
   background-image: url(header-logo.png);
   min-width: 71px;
   min-height: 34px;
   margin-left: 5px;
+  margin-right: 20px;
   margin-top: 10px;
   margin-bottom: 10px;
   background-color: #000;
 }
 
 #work_area {
-  border-image: none;
   padding: 1em;
-  border: none;
   background-color: #2d2d2d;
 }
 
@@ -318,9 +315,10 @@ QPushButton {
   border-radius: 2px;
   background-color: #2d2d2d;
   min-height: 24px;
-  padding: 3px 12px;
+  padding: 3px 8px;
   color: #28ae73;
   font-weight: bold;
+  min-width: 60px;
 }
 QPushButton:focus, QPushButton:focus:default {
   border: 1px solid #28ae73;