don't save codeblock if user does not have the rights

Prevents undefined variable $codeblock
#762
fix #764
fix #765
provide lnk to "parent" site if possible
default for unavailable languages

The default state for language translations that are not current will be
"unavailable"
Dutch translation
"empty" criterion for tags
refine computation of "master" link on clone
fix not defined variable
#765
TinyMCE 4.0.21
jPlayer 2.6.0
#765
fix #767
404 handling should be moderated by the zenphoto core 404.php script
#766
Fix #771
fixes issues with handling of deliberately bad URLs
more handling of deliberately bad URLs

Turns out that pages.php and news.php should also have the test/404
error code since they can be reached via query links when mod_rewrite is
off