BUG: to_clipboard output formatting

PR for https://github.com/pydata/pandas/issues/8305

@jreback I made the simple patch as you suggested for fixing truncated columns, although problem seems to be https://github.com/pydata/pandas/blob/master/pandas/core/format.py#L2118 called from https://github.com/pydata/pandas/blob/master/pandas/core/format.py#L411
Perhaps `conf_max` should respect if caller passes `minimum` argument so it wont truncate?

Second issue, where `index=False` was ignored (or just any other argument when `excel=False`) was because arguments were not passed to underlying function `obj.to_string()` and that was easy fix.

I added test for checking if column width greater then `max_colwidth` passes clipboard test.