MV-4: add an example table if empty

if the macro is empty, clicking the "add entry" buttons adds an example table
Revert "remove confluece 3.x support"

This reverts commit de4b3a294b9cd81df3a21e19063a4ef502659b44.

This is needed to automatically convert "insert wiki markup" into rich
text.
MV-4 selenium test for "add entry"
MV-4 fix: table can contain other macros