Generally reporting of currency gain in reports

[hugograf]

Which part and what Version?
Version: 0.10.0
[x] Internal structure (user should not notice)
[x] Improvement for the user

So far, the currency gain is not consistently presented in all reports. One supposedly profitable trade can be put into perspective by the currency gains or currency losses. The correct calculation of "currencyGainLossMC", "groupCurrencyGainLossMC" and "grandCurrencyGainLossMC" must be ensured.