Revert "Added muonlab II configuration class"

This reverts commit b1ed0cb619f2b4b3e6fa4626d29fbdf1fce9f13a.

I'm headed towards writing a very tightly coupled configuration class.
I'm not sure what to do.  I'd like to have the ability to do something
like::

    >>> muonlab.pmt1_voltage = 900

but then I'm mixing the muonlab object with a muonlab data structure.  So,
I wanted to split out the data structure as a configuration class, like
so::

    >>> muonlab.config.pmt1_voltage = 900
    >>> muonlab.read_lifetime_data()

This is better.  However, the config class needs to call
muonlab._set_pmt1_voltage(), etc.  Tight coupling.  Alternatively, the
_set_pmt1_voltage code can be moved into the configuration class, but then
the configuration class knows even more about the muonlab hardware.  Sigh.