Fix log.debug statements

[andyklimczak]

• Revert partial code from commit 2c5306e that broke(?) log.debug statements inside strategies
• Fix small typo

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  bug fix

• What is the current behavior? (You can also link to an open issue here)
  log.debug is not logging

• What is the new behavior (if this is a feature change)?
  fix log.debug

• Other information:
  log.debug from OOTB strategies are not working on latest develop
  I'm not sure if the message.log change was an intentional change, or an accidental addition

[askmike]

I removed this (in a commit for something else - apologies) because it was slowing down backtests (since most strats log a lot and all this data was pushed from the backtester -> parent process -> stdout).

But I see this basically hides all logs from the backtesters (when using the UI or API).

I was thinking the following instead:

• in the UI add a "debug" tickbox to the backtest screen, this toggles the log level of the backtester (to either log or not).
• Apply this patch so that if the backtester logs, it should stream up.
• Add documentation on how to properly set up a "create strategy environment".

What do you think?

[askmike]

I am actually applying this already, since it is currently actually a bug. Though the above question still holds.

[andyklimczak]

For sure, some type of checkbox makes sense (and even control in the code with something like this.debug = true)

[askmike]

How the config behaves in general (especially when using the UI) is grown a bit out of hand, if you are interested in the full discussion please check out #956.

Before the UI there was one config that did everything, now it is split into a few different categories (how you want everything to behave, like database stuff / how you want the UI to behave, like ports and hosts / how you want individual instances to behave, like this feature).