Allow aligning on commidity char instead of decimal separator

[entropitor]

I love this plugin. Unfortunately, it aligns on decimal separator while I'd prefer to align on the commodity symbol. It'd be nice if this plugin has support for that

[alerque]

I'd love to accept a PR that accomplished that as an option! I don't have time to make it happen right now I'd be willing to help review and tweak and contributions that come up for merging.

I don't personally like the alignment either — but my beef is that I have multiple different localized currencies in my ledgers ($1,000.00, ₺1.000,00, 1 000,00 ₸, etc.) and the plugin cannot currently handle more than one decimal separator for alignment. Hence it aligns all my USD transactions at the thousands place and TRY transactions at the decimal.

I imagine a similar problem will come up aligning on commodities any time more than one is used in a ledger.

By the way my workaround is to do alignment via hledger print, but that's less than ideal for a number of reasons. It would be great to come up with a more robust alignment system for this plugin.

[alerque]

Anybody that does try to work on this should probably take a gander at #95 before getting started.