Copyright year span

Projects may need to add the inception year and the current build year in the documentation (such as Copyright 2007-2010, where 2007 is the inception year and 2010 is the build year). To make the usage of this information easy, the build process should provide a property 'copyright.year' that contains either the inception year (if inception and build year is the same) or the span beginning with the inception year and ending with the build year.