Added ability to add sprintf variables to JText string

[writing it up now...]
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Added ability to use custom non-language string as first part (can be used for concatenating other strings)
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
[#30324] *Added ability to restrict the number of displayed results to mod_related_items (Fix #836)
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
 + [#31106] Added Belgian flag for mod_languages. Thanks Fonny Smets
Merge pull request #880 from nonumber/patch-9

Added ability to add sprintf variables to JText string - Thanks Peter.
 # [#30804] [3.x] *plug-in manager search give errors and warning for
'/','*' and '\
(Fix #1235)
Merge remote-tracking branch 'origin/master'