Drop upper bound on scientific
Encode RealFloat numbers using Scientific.fromFloatDigits

The previous code used realToFrac (fromRation . toRational) which
approximates a floating point value. For example:

 > toRational (1.2::Double)
 5404319552844595 % 4503599627370496

If you encode this Rational number to a Scientific number and render it
you get:

 > encode (1.2::Double)
 "1.1999999999999999555910790149937383830547332763671875"

Using Scientific.fromFloatDigits you get the expected:

 > encode (1.2::Double)
 "1.2"
Nicer ToJSON instance from Number and Integer
Depend on scientific >= 0.1
Bump dependency on scientific
Add ToJSON and FromJSON instances for Scientific
Merge pull request #162 from basvandijk/master

Encode RealFloat numbers using Scientific.fromFloatDigits
Fix module sorting
Fix JSON instance for UTCTime

This fixes gh-158.
Ensure that arbitrary DiffTime values are millisecond-bounded
UTCTime roundtrip does not need approximate equality
Fix instance of ToJSON for ZonedTime
Fix overflow bug in scientificToNumber
DotNetTime no longer requires an approx test
Rename release notes to changelog, for Hackage compat

--HG--
rename : release-notes.markdown => changelog
Merge
Add a new benchmark datum (gh-134)
Remove sources of compiler warnings from benchmarks
Ignore new cabal sandboxes
Add -rtsopts to benchmarks