WICKET-5466 watch out for null component; break early from method
Methods in interface are public implicitly
WICKET-5471 Store the page if it is known that it will be used in a following request

(cherry picked from commit 23172242b84704d8c95bbe168198c99d8b0f5ec4)
WICKET-5472 PackageResource#internalGetResourceStream() should return ProcessingResourceStream only when the resource is existing

(cherry picked from commit 1cc56f56aedbb9f0da0c6e1df35a441106568e72)
WICKET-5471 Store the page if it is known that it will be used in a following request

Better fix.
The page will be touched (i.e. stored). But it won't be initialized unless really used because setStatelessHint(false) is called as well.

(cherry picked from commit 3fca3415b46af58591463c7a1c8843c0e9f894ac)
WICKET-5469 ModalWindow unload warning always displayed (even if window is closed)

Always reset window.onbeforeunload on close

(cherry picked from commit 0f0be95c81c97d224de5a1b9ec7abc44dc7f149f)
WICKET-5469 ModalWindow unload warning always displayed (even if window is closed)

Use event listeners instead of property based event handler for onbeforeunload.

We don't do the same for 'onunload' because event listeners can be skipped with event.stopImmediatePropagation() and this may lead to memory leaks in IE.
WICKET-5468 UrlRenderer#renderRelativeUrl potentially appends "/" after query parameters

(cherry picked from commit d9f50272e37b62a78f6a67c9b9f3f32f024d0ab8)
WICKET-5467 NumberTextField should support "any" as valid step attribute value

(cherry picked from commit 2c3aa01aba8666f8dc358e5ae25f36e38523924d)
WICKET-5068 PageParameters missing from re-created Page
WICKET-5070 Optionally execute Callback Behavior on Re-construction after Expiry
WICKET-5001 Recovery of bookmarkable Page after Session Expiry

Rename the new setting to be Java bean complaint

suggested-by: Sven Meier
Merge branch 'master' into sandbox/preserve-page-parameters-and-execute-listener-interface-after-expiration