Merge changes from origin/7.1

74dcb6f Correct assertion message which changed due to #12915
12b6a8b Test for broken Webkit feature which causes extra scrollbars (#12736, #12727)
ea46029 Allow excluding test from the standard test suite
c171850 Disable client timeout so websockets are not disconnected when idle (#13015)
36fce65 Test for pushing for an extended period of time (24h)
54a5667 Fix compilation error
25fc48c Do not throw NPE if conversion messages is null (#12962)
26b5b67 Timeout redirect timer is reset on server activity (#12446)
d45785d Fixes right click selection focus issues in Tree. (#12618)

Change-Id: I3cef915ee46b77ca0f188296cfa343cde1ad59e6

diff --cc client/src/com/vaadin/client/ApplicationConnection.java
Simple merge

diff --cc client/src/com/vaadin/client/communication/AtmospherePushConnection.java
Simple merge

diff --cc client/src/com/vaadin/client/ui/tree/TreeConnector.java
Simple merge

diff --cc server/src/com/vaadin/ui/AbstractField.java
Simple merge