Supports POSIX ustar prefixes and GNU longlink entries

This new class is only losely based on our previous library. The
whole API was changed to make it more flexible and memory saving.

Some fisrt unit tests are included

Appending files now works at least for uncompressed tar files. Seeking
in compressed tars is not yet supported.

You can give a path and file contents in an array. However this didn't
work because the file_exist() check was done before checking for an
array

Corrected typo: ruke -> rule

Removed acronyms for "Perl" and "PERL" as Perl is not an acronym.

Internet Explorer 8 (and maybe others) seem to use different
capitalization in the ACCEPT_CHARSET header between "normal" requests
and AJAX requests. This causes a browser UID mismatch and thus an
unecessary reauthentication.

See http://learn.perl.org/faq/perlfaq1.html#Whats-the-difference-between-perl-and-Perl-

Made bin/striplangs.php executable

Made it easier to use, and consistent with the others bin/*php scripts

* added more selectors to allow different markup
* added border to make tabs more distinctive, especially in other templates

Proposed fix for #2541

added support for local style.ini files

#2541, alter section highlighting to insert a container into the DOM to hold the elements being highlighted & later remove it