Add Spread Information to bars from server data rates

When using “bars from server” as the data rate in opposite of “Tick data from server” there are just 2 options of how to generate the spreads:
1. Enter a fixed value
2. generate the spread randomly

Using “bars from server” as the data rate is obviously much faster as “Tick data from server” and as such is the preferred method especially when it comes to optimization with thousands of back test runs.
However, the spread information should be accurate also when using “bars from server” data rate. Both existing methods to specify the spreads with bars data rates do not make much sense when accurate spreads are needed and these 2 methods do not belong to a modern back testing/optimization platform as cTrader wants to be.

The solution to solve this issue is very easy: Just add the spread information to each bar stored in the history .zbars files and add a 3rd option to specify the spread source:

For more details see also:
https://ctrader.com/forum/suggestions/44294