make tables use the semantic block structure
make table delete not leave the semantic container behind
tighten up space around table
no need for column deletion to look unlike other deletions

while i'm here in this part of the code ...
other semantic blocks have .aloha-oer-block element

and those canvas-* classes look suspiciously like junky mark-up from my
mock-ups
Revert "other semantic blocks have .aloha-oer-block element"

This reverts commit c9ba4a66dcea7d1a65b8ca902d36ed1a87eedc0a.
fix tables drag handle label
fix opacity of hover state for tables
do not allow dropping blocks between tables and their container
make tables renumber when you drag them around
refactor table activation to be more readable
Merge branch '59098512-put-tables-into-a-semantic-block-so-that-they-can-be-copied-moved-and-deleted' into testing