start using ::Method::Modifiers to move hooks into DPIC6
more hook moving work
complete move of all hooks from Interchange6::Cart
ensure args passed to hooks are ref/non-ref as appropriate

- in hooks we pass scalars as non-ref with arrays and hashes as refs
- add lots of missing pod for hooks
put cart route add into try/catch - we don't want 500s
try/catch around remove in cart route + combine errors in array
correct error text in commit e8a2b071e5a
in cart route only pass cart_error tocken if there are errors
wrap $cart->set_sessions_id(undef) in try/catch during logout
add 'update' to cart route + fixup tests for lastest schema
fixup cart route update + close #40
redirect after cart route remove product if method is_get