Merge pull request #1747 from mahagr/master

Fix #1535 Update Kunena Repository Directory Structure
#1748 Installation issue (languages)
#1749 Save profile: JUser:: _load: Unable to load user with id
#1750 (J 2.5) Trash Manager - select all, selects always the half
Merge pull request #1752 from xillibit/k30_bugs10

#1748 Installation issue (languages)
Merge pull request #1755 from xillibit/k30_bugs13

#1750 (J 2.5) Trash Manager - select all, selects always the half
Merge remote-tracking branch 'upstream/master' into k30_bugs16
Merge pull request #1753 from xillibit/k30_bugs16

#1749 Save profile: JUser:: _load: Unable to load user with id
#1757 Notice in Diagnostic tool with J! 3.1.1
Merge pull request #1758 from xillibit/k30_bugs16

#1757 Notice in Diagnostic tool with J! 3.1.1
#1757 Update template of diagnostics for Joomla 3.1
Merge pull request #1762 from xillibit/k30_bugs16

#1757 Update template of diagnostics for Joomla 3.1
Merge pull request #1763 from mahagr/master

Remove 2.9.x support form KunenaForum::isCompatible(), docs update
Fix a few PhpStorm inspector warnings