Don't define Semigroup Binary.Builder instance with binary-0.8.3 and later

[RyanGlScott]

binary-0.8.3 changes its Builder representation to be a synonym for bytestring's Builder, which already has a Semigroup instance. To avoid instance conflicts, this PR guards the Semigroup Binary.Builder instance with CPP.

Fixes #65.

[hvr]

@RyanGlScott any suggestion for cabal-edits on hackage? (I haven't given this any thought at all yet)

/cc @bergmark @phadej

[RyanGlScott]

@hvr, would it suffice to retroactively change the version bounds for the binary dependency to < 0.8.3? Luckily, semigroups-0.18.1 is the only release to have the Semigroup Binary.Builder instance.

[RyanGlScott]

Urgh, Travis is failing because of a binary issue: kolmodin/binary#113

[RyanGlScott]

Revised on Hackage: http://hackage.haskell.org/package/semigroups-0.18.1/revisions/

[kolmodin]

I think the proposed fix in this PR is the correct fix.

Currently semigroups-0.18.1 has the constraint binary < 0.8.3.0 which makes binary's dependencies unable to depend on semigroups! Currently that means that I can run the benchmarks for binary.

$ cabal new-configure 
Resolving dependencies...
cabal: Could not resolve dependencies:
trying: binary-0.8.3.0 (user goal)
trying: semigroups-0.18.1 (dependency of aeson-0.11.2.0)
trying: semigroups-0.18.1:+transformers
trying: semigroups-0.18.1:+hashable
trying: semigroups-0.18.1:+unordered-containers
trying: semigroups-0.18.1:+text
trying: semigroups-0.18.1:+tagged
trying: semigroups-0.18.1:+deepseq
trying: semigroups-0.18.1:+containers
trying: semigroups-0.18.1:+bytestring
rejecting: semigroups-0.18.1:+binary (conflict: binary==0.8.3.0,
semigroups-0.18.1:binary => binary<0.8.3)
rejecting: semigroups-0.18.1:-binary (manual flag can only be changed
explicitly)
Backjump limit reached (currently 2000, change with --max-backjumps or try to
run with --reorder-goals).