Bumped copyright year.
Made code warning-free.
Converted as many mkName <const>s to use TH quoting as possible.
Added promoteEqInstanc(s) to create :==: instances after the fact.
Rewrote singEqInstances to work, even without a fix for Trac #7477.
Added support for singling class constraints (such as Eq).

Updated README.
Updated test cases.