Fix #716 crash with reset flag

Adds a `rules` key when the `--reset` flag is used so that
`Object.keys(config.rules)` doesn't fail. There were multiple
similar issues where the presence of `rules` was assumed, so
changing it once was the most straightforward solution. This issue
wasn't picked up by the tests because the tests saw the .eslintrc in
the project root, which gave the config a `rules` key and masked the
error.
Add --no-eslintrc cli flag (ref #717)

An addition to adding an on-by-default flag to enable or disable
loading .eslintrc configuration files, this new flag fixes the test
for the --reset flag by cleaning up the polluted test environment
that masked an error.