API: raise on header=bool in parsers
closes #6113

Passing `header=True|False` to `read_csv` (and brethren), `read_excel`, and `read_html` will now  raise a `TypeError`, rather than being coerced to an int.

I had thought about converting `False` to `None` but thought that could break someone's code in a very subtle way if they were somehow depending on the old behavior.  But happy to change that if it seems better.

If you want to push this in for 0.17 I can add a doc-note or this could easily wait.
