WICKET-5635 Provide a way to modify ResourceReferenceRegistry.DefaultResourceReferenceFactory externally to be used by wicket-bootstrap-less

(cherry picked from commit 6154fd6aae702ec5c23d39f6ac3ae9593da4d3b9)
WICKET-5636 Submit repeated form components on stateless forms

(cherry picked from commit e50f298107ea2d8526a201d44a7200240747e80b)
WICKET-5648 CookieUtils - add #loadValues(), make #getCookie() public, properly initialize from the defaults

(cherry picked from commit b5e29819b1aa75ef8648c6ebaf0b5ebf72bdb2da)
Optimize imports
Minor improvements:

- Java 7 diamonds
- append char instead of String
- do not calculate the idValue in a loop
WICKET-5640 Reduce the mangling of HTML markup in the Java code as much as possible
WICKET-5650 Make is possible to position the choice label before/after/around the choice

(cherry picked from commit f9668b5ea6d4dfc196409dff588a06dd5b9ea571)
WICKET-5651 Add TagTester#getChild(String tagName) method

(cherry picked from commit 5d47267e94ba2eae0d188132774cc2dc61b03f68)
WICKET-5650 Make is possible to position the choice label before/after/around the choice

(cherry picked from commit a92f8447256235783993ca0ae47678ee97240246)
Merge branch 'master' into 5640-less-mangling-of-html
WICKET-5640 Reduce the mangling of HTML markup in the Java code as much as possible
WICKET-5640 Reduce the mangling of HTML markup in the Java code as much as possible

Add usage and deprecation text
WICKET-5643 WebPageRenderer should bind a Session if redirect is
required and the session is temporary.

Added a warning log if a null session id is provided.
Fix the build
Whitespace cleanup. No functional changes
Fortify the async nature of the FilesTest tests.

We should null-ify the file/folder to be deleted so it is eligible for GC.
WICKET-5643 WebPageRenderer should bind a Session if redirect is required and the session is temporary.

Check for "" too.
Log as an ERROR and do nothing more to really prevent serving a response to another client

(cherry picked from commit 8e24bfbd46a37103ea635bda63988c50c84d606e)
WICKET-5657 wicket-autocomplete may fail after preceeding Ajax request
WICKET-5655 clear FLAG_INHERITABLE_MODEL reliably