create connector class with constructor
add admin configuration form
move classes into sub directory
stub out connector actions
use masked field for password
don't mask password

the password is only used for changing the password (not displaying it),
so don't bother masking it
set up data structures for tax calculation
populate tax calc data structures from cart
build SOAP request xml
send SOAP request
log curl errors to file
use pre-defined ISO 8601 date format
stub out SOAP response parsing
parse CalculateSalesTaxDueForOrder results
log xml parsing errors
set more reasonable default tax rate
rough out compliance check request
move if block inside try/catch, rename form ID
fix parens after rename
define form fields in separate function