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
Merge remote-tracking branch 'remotes/upstream/master' into patch-9
Merge pull request #880 from nonumber/patch-9

Added ability to add sprintf variables to JText string - Thanks Peter.