Allow customization of how message preparation is done in prepareLog (appending stack trace of throwable, etc)

It'd would be nice to be able to customize how the message to be logged is handled/modified. Current behavior always adds the stack trace of the throwable (either sets it if message == null, or appends it).

A stack trace in the log line might not render well in the crash reporting tool, and it would be useful to have more control over what *exactly* gets logged/reported when I call Timber.e(t1, m1, args1...);

This is a first shot of what I'm looking for:
https://github.com/brAzzi64/timber/tree/prepareMessage

Thoughts?

Thanks!

Start by reviewing the prepareLog behavior described in the issue and the linked prepareMessage branch, then trace how Timber.e(t1, m1, args1...) prepares its message. Done means agreeing on and implementing an extensible customization point that lets callers control throwable stack-trace handling and the exact logged output.

Written by the indexing model from the issue text.