added multicolumn (#21)
added multicolumn (#21)

* improved readability

* added support for caseless litterals

* removed useless import

* improved readability

* divided types and names in two columns

* removed useless comment

Co-authored-by: Richard Hull <ac21ac6c9b0b667cee198fa62095a16619b4e490@yahoo.co.uk>
rm-hull/sql_graphviz