Preparing for version 0.4

 - Configured version number and modified "new in version".
 - Added a few spaces in validity intervals in tables.
 - Fixed error in code sample
Added code to test cformat
Added test cases for cformat's %U and %W directives
Added cformat to GregorianCalendar

This commit includes fixed test data
Added cformat to IsoCalendar

This commit includes fixed test data
Version 0.4 release