optimised functions to read and write int16/32/64 (development)

 Optimised functions to read and write int16/32/64 from strings, bytes
 and bigarrays, based on primitives added in version 4.01.
 .
 The library implements three modules:
  * EndianString works directly on strings, and provides submodules
    BigEndian and LittleEndian, with their unsafe counter-parts;
  * EndianBytes works directly on bytes, and provides submodules
    BigEndian and LittleEndian, with their unsafe counter-parts;
  * EndianBigstring works on bigstrings (Bigarrays of chars), and
    provides submodules BigEndian and LittleEndian, with their unsafe
    counter-parts.
 .
 This package contains the development files.