Remove row coloring of transaction entries

As transactions are now listed in a separated view,
the coloring is not needed. And I do not like that much.
Create columns with column support util

Enables custom column layouts, sizing, etc.
Add export action to dividend performance view
Allows to store several column configurations

Using the save menu, users can now persist custom
column configurations (say one simple one as overview
and another one for the dividend prognosis)
Add option to remove all columns of a column group
Refactored performance snapshot: move record class to new file
Added delta column to dividend performance snapshot

delta = market value + dividends - cost
Added market value column
Renamed dividend performance to security performance

Since all values of the security performance record are now available
in the dividend performance record, it makes sense to have only one.