Define "block container element"

[gsnedders]

From https://lists.w3.org/Archives/Public/www-style/2012Sep/0358.html:

• RESOLVED: Accept Anton's proposed edits for defining "block container element"
  http://lists.w3.org/Archives/Public/www-style/2012Sep/0041.html
  with editorial reorg of defining paragraph by fantasai
  http://lists.w3.org/Archives/Public/www-style/2012Sep/0356.html
  Open issue on whether/how "principal box" needs to be defined.

Anton summarised the resolution's edits (i.e., incorporating the editorial reorg) in https://lists.w3.org/Archives/Public/www-style/2012Sep/0369.html

https://www.w3.org/Bugs/Public/show_bug.cgi?id=18930 was filed for the open issue. This should get migrated to GitHub. #2783

https://www.w3.org/Style/css2-updates/REC-CSS2-20110607-errata.html#s.9.2a was the edit (inc. s.9.2.4a and s.17.4b) in the 2.1 errata.

[gsnedders]

Moved that Bugzilla issue over as #2783.