Extended functionality for missing data and own data

Extended functionality:

• Account for cases where countries or regions are specified with 'exclude ...'

• Possibility to add custom countryfile for own mappings

• Not found value can be specified also in the CLI version

• Automatically detect input format (ISO2, ISO3, ISOnumeric)

Some bugfixes:

• Change ISO3 for Romania from ROM to ROU (bugfix)

• Change ISO3 for Congo from COD to COG (bugfix)