Merge branch 'master' into proxyconnect

* master: (169 commits)
  added PCRE UTF-8 checks to do=check FS#2636
  avoid multiple paralell update checks
  fix regression bug in HTTPClient FS#2621
  changed PAGEUTILS_ID_HIDEPAGE to has BEFORE/AFTER
  TarLib code cleanup
  TarLib: fixed appending in non-dynamic mode
  fixed third method of adding files in TarLib
  fix lone zero block in TarLib created archives
  fix use of constructor in TarLib
  Slovak language update
  Korean language update
  Latvian language update
  added event PAGEUTILS_ID_HIDEPAGE
  added test for isHiddenPage()
  removed redundant variables in tpl_include_page() (because of 3ff8773b)
  added cut off points for mobile devices as parameters to style.ini
  Corrected typo: ruke -> rule
  Persian language update
  Spanish language update
  russian language update
  ...