[Console] fixed progress bar jumping
Issue 5288 fix 
[Routing] removed tree structure from RouteCollection
adjusted tests
added upgrade instructions
updated CHANGELOG for 2.0.19
update CONTRIBUTORS for 2.0.19
updated VERSION for 2.0.19
updated CHANGELOG for 2.1.4
updated VERSION for 2.1.4
[HttpKernel] Add DI extension configs as ressources when possible
Bugfix for creating cookie on loginSuccess in AbstractRememberMeServices
Fix problem when 1 column identifier in propel is a string.

The ModelChoiceList thinks it can be used as the index of the ChoiceList, when it can only be used if it is an integer.
[HttpFoundation] added a small comment about the meaning of Request::hasSession() as this is a recurrent question (refs #4541)
removed unused attribute from routing.xsd
it should be possible to define the defaults, req. and options in any order, just like in YAML
refactor to an xsd:group
make id attribute required
add default for pattern for clarity
removed wrong routing xsd statement `mixed="true"`

mixed="true" means that the element could contain both text and other elements, e.g.
`<requirement key="_locale">text <subelement /></requirement>`
But this wrong and such a definition would not even validate against the scheme as the xsd does not define which elements would be expected inside.