Merge changes from origin/7.1

Merge changes from origin/7.1

419c6c7 Implemented Focusable in MenuBar (#7674)
a4f1277 Fixed NPE in ApplicationRunnerServlet (#12145)
08d365a Fixed slider value initialization on HSV and RGB tabs of ColorPicker. (#7863)
da480bd Fix VaadinService.findUI to throw Error if UIConstants.UI_ID_PARAMETER is not set (#11943)
6291a50 Ensure that Slider diffstate always contains "value" (#12133)
7e7e698 32x32 favicons added, replacing the old favicons (#12143)
1702059 Replace printStackTrace with getLogger().log() (#12147)
b421d6e Updated Javadoc for Table.getColumnAlignment fixing #6810
414e3bf Fixed an error in CustomComponent JavaDoc (#10038), and some improvements.
4583d07 Fix NPE in Like.java (#10167)
6c4da29 Ensure table's cells aren't refreshed if table is detached. (#9138)
e37464c #11638: Ending an imported SCSS file with a comment causes an error in the Sass
478eeb5 Test using Jetty 9 (#12124)
f7cc72d Close only combobox on escape, not the window (#12163)
9a9b0a5 Automatic test for escape closing window from combobox (#12163)
ae565a2 Fix bug in PopupDateField where locale was retained incorrectly if changed while popup was open (#12153)
d7a64fd Enable native scrolling in home screen apps on iOS 6+ (#12149)
4a04f00 Add test case for testing ClickEvent after dragging button (#7690)
775c969 Make UploadInterruptedException visible (#12070)
6a4bbe5 Set heartbeat response Content-Type to text/plain (#12182)
e4011c6 When InputStream cannot be opened while writing static resource response, display 404 instead of 500 (#10920)
20162db Set current instances when calling UI.push from VaadinSession.unlock (#12168)
94c0f86 Ensure VaadinSession.service is set up by storeInSession (#12204)
23ed487 Attempt to get GAE lock for UIDL requests (#12211)
7f52b2e Improved AbstractClientConnector performance (#12219)
a934261 Improving performance of ConnectorTracker (#12218)

Change-Id: I810124d60c22d4d0ab837a19eb9c2689951864b5