Unit testing, minor cleanup/refactoring

NOTE::: all changes are backwards-compatible; future releases may raise an "E_USER_DEPRECATED" error in cs_versionAbstract (it's deprecated already, technically).

 * new cs_version class; works like cs_versionAbstract, except it's not abstract.
 * deprecated cs_versionAbstract, extends cs_version for backward compatibility
 * changes to extend cs_version (later, it will probably become a property)
 * fix PHPUnit config, test filenames, and added bootstrap file
 * minor cleanup of SVN-related comments
version bump