add ability to manually exclude files from search suggestions.

Use the hdf tag excludeFromSuggestions=true

Change-Id: If2f0f0f19f0e3b27adf69e09b9527e8d97213db5
diff --git a/src/com/google/doclava/Doclava.java b/src/com/google/doclava/Doclava.java
index 38f40d6..61b1c6c 100644
--- a/src/com/google/doclava/Doclava.java
+++ b/src/com/google/doclava/Doclava.java
@@ -911,7 +911,9 @@
           String dirName = (webPath.indexOf("/") != -1)
                   ? webPath.substring(0, webPath.indexOf("/")) : "";
 
-          if (!"".equals(title) && !"intl".equals(dirName)) {
+          if (!"".equals(title) &&
+              !"intl".equals(dirName) &&
+              !hdf.getBooleanValue("excludeFromSuggestions")) {
             data.setValue("docs.pages." + counter.i + ".label", title);
             data.setValue("docs.pages." + counter.i + ".link", webPath);
             data.setValue("docs.pages." + counter.i + ".tags", tags);