Update version of Vaadin

[skrchnavy]

Current version of Vaadin: 7.1.8
Current version is 7.3.3

It would be good to update to newer version then used to have benefits from new features.

[skrchnavy]

Analysis of benefits of 7.2.6:
enhancement issues suggestions:
GridLayout hides empty rows now, because it didn't before, there were empty spaces after removing rows and "refresh" was used and can be removed
7.2.0 #12466 Add support for poll listeners = Refresher add-on functionality in vaadin core
7.2.0 #13222 com.vaadin.ui.Upload introduce new "SelectionListener" = "can be used to implement a preview of sorts, showing the name, type, and size of the file (or files, using multiple) before uploading."
support for tomcat 8

think to look out for:
7.2.0 #4054 Change ComboBox to be immediate by default
and
7.2.0 #8029 Change setImmediate default to true for most components
this can cause some issues with premature displaying content?
nice perks:
compilation permutations collapsed (unnecessary / duplicate removed?) = shorter compilation time

[skrchnavy]

migration to 7.2.6 is in https://github.com/UnifiedViews/Core/tree/feature/510_vaadin_migration_7.1.8_to_7.2.6
commit ff3539e

[skrchnavy]

issue is extended in new issue #276

[skrchnavy]

@skodape shall be closed together with #276.

[skrchnavy]

closed - to be included into v1.6.0 - see #276 and #245 for more details