[TW-1838] Format UDA in custom report

_Christof Hagedorn on 2016-08-02T13:16:40Z says:_

It would benefit many cases where UDAs are used to have an format property to be used in a definition of a custom report:

task config report.simple.columns 'id,myuda'
task config report.simple.format 'int, %.2f'
or
task config report.simple.format 'int, float(2)'

Instead if the current fixed format with 6 decimals
f.e.
12.000000
it would be posibble to truncate to a number of decimals or integer
f.e.
12.00, or 12