To update this zen cart module Include and Exclude Tax in Prices (Nett/Gross)
New updated module must
a) be lightweight and not touch core files, but use overrides and new files only
b) stay true to the security standards of the 1.5.x fileset, and not break PCI rules.
c) be PHP 5.3 Safe
d) fix calculation errors occasionally experienced on the shopping cart side-box
e) well written and clear installation instructions.
f) well written and clear un-install instructions, including correct MySQL statement.
g) Written using GPL, as I would like to have the module shared with the Zen Cart Community, so other can benefit (Optional)