OptionsView/Viewer typeclass canonicalizations

This switches the OptionsView/Viewer typeclass to use more canonical
approaches and helper methods. This uses a context bound instead of an
explicitly specified implicit argument. Additionally, this adds an
apply method to OptionsView to enable more canonical use of the
OptionsView typeclass.

With this, you can now do things like `Viewer[FirrtlOptions].view` in
addition to the old (and still available)
`Viewer.view[FirrtlOptions]`. Uses of the latter are updated to use
the former.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>