1.4 2018-03-01

• Improved interface for the Interval library by using sub-modules
  and standard mathematical names. In particular, all operations —
  including infix operators — are in a sub-module I which can
  conveniently be used to introduce local scopes after issuing open Interval.

• Improved pretty-printing functions allowing to pass the format of
  the interval bounds.

• The library functions now signal errors by exceptions
  Division_by_zero and Domain_error that are local to
  Interval.

• The Fpu module has been redesigned: the rounding up or down of
  functions is controlled by the sub-module (Low or High) to which
  they belong. This allows for natural expressions such as
  Low.(x**2. +. 2. *. x +. 1.).

• Jbuilder/dune is used to compile and install the library.

• TravisCI and AppVeyor continuous integration ensure the library
  works on a variety of OCaml versions and platforms.