CSSTidy Code

- Copy to clipboard for Firefox

- Small grammatical clarification in English translation re: CSS validator

- separated German from English to be consistent
- removed trailing ?>
- added entry (in English) for each language re: clipboard in Firefox
- added note about orphaned array slots
- changed test for languages to in_array in order to be more maintainable in the future with additional languages

- Small XHTML 1.0 Strict formatting fix
- Added option in Firefox to copy to clipboard (depends on having a preference set) and added a warning about security concern when not enabled

Extra documentation for CSSTidy testing suite.

One more test and bugfix

Added color test

Unit test cleanup and more unit tests + bug fix for number optimisation

- Add discard_invalid_selectors cfg and functionality; this fixes some of the duplicate combinator problems
- Minor comment formatting changes
- SETTINGS and FULLEXPECT support added to csst tests

Minor formatting changes:
- Compress extended if/else statement to indicate chaining
- Remove trailing ?>, it's not necessary in PHP!
- Add a custom harness for all unit tests