Support named capture groups in custom regexes

[n0Oo0Oo0b]

Currently the only way (that I am aware of) to 'ignore' a field using a custom regex is to include an empty capture group. However, this means that if the field is filled in elsewhere, re-syncing cards will overwrite it with an empty string.

I think the best solution is to support named capture groups that correspond to each field. Fields that are left out won't be included in the HTTP request and thus won't be overwritten. This also removes the current field ordering limitations since the named groups can be in any order.