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

note: we recommend to NOT use H1 elements in the sidebar for semantic
reasons

Replaced it by the old tpl_include_page() and made it more flexible by adding a boolean $propagate parameter.
(It's false by default for backwards compatibility reasons. Should it rather be true? That would probably be what most users want.)

This reverts commit ea62d531.

Update template footer with HTML5 icon (FS#2619)