Fix spin-offs calculations

[nihn]

This diff fixes Spin-Off cost calculations (both for source and dest shares). Details of the calculations can be found in the comment of the main method. As we do not have a good DB for spin-offs the "source" share has to be provided by user during the run, the adjustments to the prices are then explained in generated .pdf file.

Additionally:

• Adding few missing transaction types to Schwab parser.
• Better error handling here and there.
• Move transactions (disposals, acquisitions, portfolios) to the instance variables to avoid passing them around all the time and making the class easier to understand (IMHO).

I'll add tests after initial review round.

[KapJI]

Can you rebase on the latest revision?

Btw, will it work correct for B&B case like in #511?

[nihn]

I don't think it will change anything for that B&B case as I am not touching stock splits but B&B should be handled correctly in case of spin-offs (AFAICT, as it just modifies the pool price, I am not tax advisor though :)).

[nihn]

Any idea why the signals are failing? I pulled the branch and it works on my machine:

[vmartinv]

Any idea why the signals are failing? I pulled the branch and it works on my machine

You're not including the spin_off_handler file in the commit.

[nihn]

You're not including the spin_off_handler file in the commit.

How did it work before is beyond my understanding though, thanks! :D

[KapJI]

Thanks for working on this! 🚀