Document the group_corrections option
Keep the default config options in a dict and make the “default” parameter of config.get() optional

the Config object now also optionally takes a dict of default values
in its constructor.
Change the API of Config.get_by_tabname

Make the "default" parameter optional and thus move it to the end of
the command with the other optional parameters.

And change all the calls.
Remove the (sometimes wrong) default values in the config.get() calls
If the whitespace_interval value set in the config is null or negative, don’t send any
Make the runtime changes to max_lines_in_memory useful