Add information unit

Bit, byte, kilobyte...,petabyte, exabyte.
Generate code
Implement constants for tests

Fixes intentional compile error by generated code for new units, which
ensures all units have tests.
Merge pull request #35 from InitialForce/feature/infounit

Add units of information



Bit, byte, kilobyte and so on up to exabyte.

Fixes #31