Merge pull request #2556 from xillibit/k30_bugs4

Update readme and pre-requiements check
Fix for K3.0 : Lightbox : Long file names are not trimmed #2547
K3.0 With attachments-limit you can uploading them without limit #2558
K3.0 | The declaration "Show Super User in user list" contradicts itself #2559

Fix desc language
Change setting to Extra-Userlist
Merge pull request #2563 from xillibit/k30_bugs11

Fix for K3.0 : Lightbox : Long file names are not trimmed #2547
K3.0 | The declaration "Show Super User in user list" contradicts itself... #2565
Merge pull request #2561 from xillibit/k30_bugs10

K3.0 With attachments-limit you can uploading them without limit #2558
Merge pull request #2565 from 810/master-13-7

K3.0 | The declaration "Show Super User in user list" contradicts itself...
Fix for K3.0 : Long file names are not trimmed for attachments #2547
Merge pull request #2568 from xillibit/k30_bugs11

Fix for K3.0 : Long file names are not trimmed for attachments #2547
K 3.0: string length of "last post" subject on index pages #2570