relax SVN archive

Switched to a different sectioning style in the test suite.

The relax test suite now uses the functions from lib.text.sectioning for more consistent titles.

Merged the generic_fns.sys_info module into the info module.

Renamed the generic_fns.relax_re module to lib.regex.

Added a sanity unit test for the lib package to make sure it is the relax lib package.

Updated the lib package __all__ list.

Spun out some functions of generic_fns.model_selection into the new lib.model_selection module.

Shifted the generic_fns.xplor module to lib.xplor.

Reverted revisions r19065, r19066 and r19067.

The command used was:
svn merge -r19067:19064 .

The idea of the data_store.control absorbing most of generic_fns is not so good!

Renamed data_store.lib to data_store.control.

This is due to too many clashes with the lib package.