Fix javadoc typos
Remove unused protected classes

These were meant for the deprecated NamedMatcher and NamedPattern
classes, which were removed in 0.2.1 (REGEX-19).
Allow parentheses in character class (REGEX-20)

Character classes allow parentheses for literal matching and do not
require escapes. Pattern#countOpenParens did not account for that,
which threw off the indexes of groups that followed such character
classes.

Fixes Issue #1 in github, REGEX-20 in JIRA.
Bump version in README.md