PHP Password Validation: Generate and validate passwords based in rules

Utility class for password generation and checking.

This is utility class for password generation and checking according to custom 
password policy rules.

Password characters may include several subsets of characters: letters (latin and utf-8 as well),
digits, symbols. This sets of characters are fully customizable as well as other
password generation configuration params: min_length, letters_count, capitals_count,
numbers_count, symbols_count.

Default password policy check rule is min_length. Another custom ones may be added
to class instance by means of regular expressions. See unit test file for usage
Unit test provided in ../tests/ directory.
Short usage example provided in ../tests/example.php file. Also see unit test file
for possible configuration values

Public methods usage: see appropriate doc comment.