Advanced search: Add exclusion patterns

All files with full file path matching one of the exclusion patterns are
ignored in the search.
Searching with "git grep" now requires git >= 1.9

Change-Id: Ied5d11499bc1ff21247e50f8e146e8e5011dd2c1
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

doc/src/vcs/creator-vcs.qdoc

@@ -58,7 +58,7 @@
         \row
             \li \l{Using Git}{Git}
             \li \l{http://git-scm.com/}
-            \li Git version 1.8.0, or later
+            \li Git version 1.9.0, or later
 
                 Gerrit version 2.6, or later
         \row