Renamed AbstractTransactionVisitor to Calculation
Added dividend values to security performance

- number of payments
- sum of payments
- total dividend yield
Temporarily removed dividend performance columns

As the dividend prognosis is rather experimental (short timeframe,
based only on data of shares held), I remove it in order to concentrate
on a version to be released.

Branch 'feature_dividends_prognosis' contains the complete code.
Alternatively, use 'git apply -R' to reapply this commit.
Added support for menu labels and tool tips for configured columns
Fixed and translated columns labels for dividend columns