lua-nucleo/table: include tpretty

Feature #1308
test/cases/0180-table: fix test to match last changes in lua-nucleo/table
AUTHORS: add new contributor
test/cases/0290-tstr: fix compatibility with LuaJIT 2
test/cases/0290-tstr: fix bug made in last commit
test/cases/0330-tpretty: fix compatibility with LuaJIT 2
checker: allowing smart error messages