Changes Localizer and Unlocalizer names

As everything is in the ValueParsers namespace
the current nammig was very missleading for the
expected scope of the classes and interfaces.

They should only be used for numbers and thus
should reflect this in the name as we are not
using further namespaces in DataValues (yet)

ChangeLog is also updated

No need to make a release after this, this is just clearing stuff up ready for the next one...