#198 fixed, exceptions thrown by used Mappers aren't properly handled in the generated code
#198 fixing comments @agudian and applying throws clause to all MappingMethods
#198 adding unit test for type conversion
#200 Simplifying definition of conversions
#200 Formatting; Fixing some typos
#187 introducing constant mapping
#187 adding unit test to make sure that reverse mapping also works for source constants
#187 adapting for #198