Fix: Length of guest usernames not checked, refs #836

* inc/datahandlers/post.php
  * added verification of username for guests input using user datahandler
* newreply.php / newthread.php
  * added verification of username for preview
* inc/languages/english/datahandler_post.php
  * added language strings for possible error messages in post author validation
Fixes #992 User CP Redirects

User CP forms self redirect instead of redirecting to the UCP index
Fixes #995 Member list has wrong code
Small improvements in theme
Merge pull request #996 from martec/smallimprovtheme

Small improvements in theme
Fixes #1000 - Statistics Settings Spelling Mistake
Fix pid page issue
Merge pull request #1003 from martec/fixpageissue

Fixes #1002 : Some issue with typecast int
Fixes #990 - Quick Reply box gets shaded af...

#990 - Quick Reply box gets shaded after posting a reply
Merge pull request #1001 from ATofighi/patch-12

Fixes #1000 Statistics Settings Spelling Mistake
Fixes #1005 The private read template is aligned center
Fixes #977 Lite (Archive) Mode - SQL ERROR related to 'status' column and mysql_db_inserts.php
Merge pull request #993 from jnschrag/feature-992

Fixes #992 User CP Redirects
Update mybb.css
Merge pull request #1011 from martec/fixpointersceditor

Fixes #1008 : Cursor pointer issue in Sceditor with theme mybb.css
Update mybb_theme.xml
Update contact.lang.php
Update mybb_theme.xml
Update contact.lang.php
Fixes #330 Permaban Warning Levels don't work