Verify the connector hierarchy if assertions are enabled (#12271)

Change-Id: I87632abe9d86927b7ba4254724fedfdb04513205
Fix issue with hidden component cells in Table and TreeTable #12119

Change-Id: I2f491d04ff177f7f0ce104c96b1c4a84ee7a2bc0
Fixes light theme window sprites #12171

The close buttons images for the Window black theme was mistakenly
added to the white theme sprite and ended up in the middle of the
light theme window. Moved the black theme button images to the
black theme sprite.

Change-Id: Ieaaaa1b404f1d623c61fe7cfecb4996d96904b27
Fixes button :active state on firefox #12126

When doing event.preventDefault() firefox will not trigger the :active
selector intentionally (see
https://bugzilla.mozilla.org/show_bug.cgi?id=771241).

Event.preventDefault() was added to prevent text selection in #10917
but it actually is not needed since the button also uses the
user-select:none css attribute which effectivly prevents the text selection.

Also now applying the previously browser specific (ie,opera) .v-pressed
classname to all browsers to make styling of the pressed state a bit easier
to do for all browsers and not reliant on the :active pseudo-class which is a
non-standard pseudo-class.

Change-Id: Ic67c0abb9d0bf8f47b817609f2928aa8fff3e82b
Fixed wrong classname in WindowThemes TB test #12171

Change-Id: I23ce7ba8a87c119ada78bba1d4735c4d8404b4f8
Merge changes from origin/7.1

a53d487 Verify the connector hierarchy if assertions are enabled (#12271)
e9f3fcc Fix issue with hidden component cells in Table and TreeTable #12119
cbab936 Fixes light theme window sprites #12171
938d412 Fixes button :active state on firefox #12126
4219227 Fixed wrong classname in WindowThemes TB test #12171

Change-Id: I09bdb2fd0d16acad2afd84c544b26223d5f603a1