FilterParser can parse filter string including special chars.
Merge branch 'master' into bugfix/filter_parser_cannot_parse_blackets

Conflicts:
	lib/net/ldap/filter.rb
	spec/unit/ldap/filter_parser_spec.rb
Merge pull request #157 from satoryu/bugfix/filter_parser_fails_to_parse_blackets

Bugfix/filter parser fails to parse blackets