f216880fb841d883a56129d637c75fd38851d49d Fix: Improve performance for button selection and column visibility

https://datatables.net/forums/discussion/80798

374b812d12facd00cd1cfd483c4aea23957d76dd Dev: Correction to performance improvement for column visibiliy - wasn't
correctly filtering by column

bb348c803e8db02050f8c45bf38e45d407d10251 Fix: Performance - faster button look up by storing a node reference rather than traversing the DOM

Sync to source repo @bb348c803e8db02050f8c45bf38e45d407d10251

Author: dtbuild

datatables.json

@@ -14,5 +14,5 @@
     ],
     "src-repo": "http://github.com/DataTables/Buttons",
     "last-tag": "3.2.2",
-    "last-sync": "73cdaad7eff108065037d3b715853e8f0c867714"
+    "last-sync": "bb348c803e8db02050f8c45bf38e45d407d10251"
 }