Add autoreload flag that is on by default

[yotamN]

It would have made more sense to make auto reload off by default but because we don't want to break backwards compatibility we keep it on by default. In order to ease any future migration the auto reload flag exist and will currently do nothing (except overriding any previous --no-auto-reload flag).

Resolves #83

[oleavr]

@yotamN Thanks! Could you tweak the commit messages so they include a tag where appropriate? E.g. repl: Fix xyz. Otherwise this looks ready to merge.

[yotamN]

Sure, fixed it

[oleavr]

Thanks!