Change to font colors of sel/unsel tabs and also highlight

Font color of all tabs have been changed to black to have better
contrast. Also, selected tab with inactive view will have grey
highlight, selected tab with active view will have blue highlight.

bundles/org.eclipse.ui.themes/css/e4_preview_win.css

@@ -71,15 +71,15 @@ ColorDefinition#org-eclipse-ui-workbench-ACTIVE_NOFOCUS_TAB_BG_END {
 }
 
 ColorDefinition#org-eclipse-ui-workbench-ACTIVE_NOFOCUS_TAB_TEXT_COLOR {
-	color: #3b3b3b;
+	color: #000000;
 }
 
 ColorDefinition#org-eclipse-ui-workbench-ACTIVE_TAB_TEXT_COLOR {
-   color: #3b3b3b;
+   color: #000000;
 }
 
 ColorDefinition#org-eclipse-ui-workbench-INACTIVE_TAB_TEXT_COLOR {
-   color: #3b3b3b;
+   color: #000000;
 }
 
 .MPartStack {
@@ -160,7 +160,7 @@ CTabFolder Canvas {
 }
 
 .MPartStack{
-	swt-selected-tab-highlight: #2160bb;
+	swt-selected-tab-highlight: #A0A0A0;
     swt-selected-highlight-top: false;
 }
 
@@ -171,13 +171,13 @@ CTabFolder Canvas {
 
 /* text color and background color of unselected tabs in editor*/
 #org-eclipse-ui-editorss CTabItem{
-	color: '#6A6A6A';
+	color: #000000;
 	background-color: '#f8f8f8';
 }
 
 /*text color and background color of selected tab in editor */
 #org-eclipse-ui-editorss CTabItem:selected{
-	color: '#3b3b3b';
+	color: #000000;
 	background-color: '#FFFFFF';
 }