add options to NewWithDefaults, update bool

[emar-kar]

This update adds options into NewWithDefaults function and makes boolean check case insensitive

• includes small docs changes and comments update

[bigkevmcd]

@emar-kar Can you rebase and fix the conflicts for this?

[emar-kar]

@bigkevmcd yeah, sure, will do today, a little bit later

[bigkevmcd]

I'm not so sure about this change.

While I appreciate the intent, this behaviour is different from the Python ConfigParser?

https://docs.python.org/3/library/configparser.html#configparser.ConfigParser.getboolean

Having said that, it doesn't seem to be a massive deviation, let me think about this a bit more.

[bigkevmcd]

The NewWithOptions change looks good tho'.