Doc updates for v0.4.2 release

Updated top-level documentation files for the release of version 0.4.2.

Version 0.4.1, incorporating minor changes to better support performa…

…nce testing.

Version 0.4.0

CIF API public release 0.4.0, featuring updates including
- CIF output in CIF 1.1 format
- automatic, on-demand data type coercion for CIF data value objects
- support for a new value property tracking whether that value is
  considered quoted
- new public utility functions for string analysis
- various bug fixes and minor improvements