The latest release (0.8.3) provides a general mechanism for formatting numeric custom columns. There is a new box in the column definition for entering a
format specifier to format the number. The tooltips in the column definition box provide a few examples.
Note that although the format specifier looks like a template, it is not. The template language also uses format specifiers, which is why they have a similar look.
The format to do what you asked would be {0:.2f}