Add converter for primitive number types.
We need a system of converters (originally envisioned as part of Ploop) to convert common primitive values. Eventually we can create a converter strategy and have a default implementation that converts e.g. from int to long and vice-versa, but for now we at least need automatic conversion for the primitive number types. We can just default to the default converter for now and punt on additional converters.
Now that TURF (in ) will be turning all urf-Integer values as long, this becomes especially important. We need to be able to say configuration.getInt(), for example, and retrieve an int value value even if stored as a long.
An open question remains of whether we store the converter in each configuration, or if we store a configured converter accessed via Clogr perhaps. Maybe there is a hierarchy of converters. Maybe they are pluggable. Maybe we provide them to a configuration factory.