Merge changes from origin/7.1

Merge changes from origin/7.1

de53191 Fix for #12279  (caret jumps when formatting in RTA).
fca0f7a Add <br> as empty representation for webkit (#12490)
6dcece8 Allow creating TextBox or SuggestionPopup when extending VFilterSelect (#12491)
22fcb44 Include unobfuscated file used by test in the war (#12468)
bc90a58 Unified xml files to end with new line
3d01d74 Reduce Ivy resolver spam to a minimum (#12510)
1e73ca8 Fix keystore path to correspond to the Vaadin 7 directory structure (#12520)
dcf9c61 Protect CurrentInstance instances from garbage collection (#12509)
24ffbc2 Allow storing and restoring null instances in CurrentInstance #12509
0d79a84 Added a comment that hopefully explains the NULL_OBJECT #12509
e4d99b3 Use non-obfuscated version of vaadinPush.js when not in production (#12527)
3a31dfe NullPointerException in TableQuery.fetchMetadata() (#11403)
4659797 fixed incorrect name for close-pressed.png for windows in black theme (#12563)
9b05257 Test for push with streaming based on Table
3cafce3 NullPointerException in DateToSqlDateConverter (#12284)
3a4351f Ensure PushConnection is properly cleaned up on disconnect (#12226, #12522)

Change-Id: I44f3d5f003e62e7ab86a22188b22933491226868