[boost] [units] Pull request and RFC: information unit definitions for Boost.Units

Link to PR: https://github.com/boostorg/units/pull/3 Description: Adds unit definitions for standard units of information: bit, byte, nat, hartley, shannon. Defines a new unit system boost::units::information for convenient manipulation. Also includes IEC binary prefixes: kibi, mebi, gibi, tebi, pebi, exbi Example code: https://github.com/erikerlandson/units/blob/info_units/example/information.c... Unit testing code: https://github.com/erikerlandson/units/blob/info_units/test/test_information...