Avoid unit insertion
Avoid ugly `e -> (())`
Deal with deprecation warnings from Scala 2.11

This is only for the warnings which might be fixable without breaking
support for Scala 2.9.
Address Scalaz-related deprecation warnings
Merge pull request #760 from Blaisorblade/topic/deprecation

Reduce deprecation warnings
Use typesafe equality in an example

This prevents the sort of breakage in
c5980d619dd624288180383125a5dc09ed6b997e (which fixed a (spurious)
warning which should have been an error).
Merge pull request #761 from Blaisorblade/topic/equals

Use typesafe equality in an example