Frontend: Some context menus and buttons of dialog boxes are not translated

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Start the frontend
2. Rightclick any text field (i.e. chat or team name)
3. Rightclick a scrollbar
4. Provoke a dialog box (i.e. request to delete a team)

What is the expected output? What do you see instead?
After No. 2: I expect to have the strings in my language. But I only get them 
in English. This particular context menu is for copy, paste, etc.
After No. 3: The same problem as for No. 2.
After No. 4: I expect the buttons to be in my language. But I only get them in 
English. In this particular example, the strings are “OK” and “Cancel”.

What version of the product are you using? On what operating system?
I use GNU/Linux and can reproduce this in the following Hedgewars versions:
- (probably earlier versions than 0.9.20)
- 0.9.20
- Git f488421…

Please provide any additional information below.
I have found no place where I was able to translate those strings, but they 
clearly should be translatable.

Original issue reported on code.google.com by almikes@aol.com on 10 Dec 2014 at 5:27

[GoogleCodeExporter]

So, I'm going to guess that your OS is in English, not locale.

Original comment by kyberneticist@gmail.com on 10 Dec 2014 at 4:43

[GoogleCodeExporter]

Well, I have set the language in the Hedgewars settings to “system 
language” and most of the frontend is in German. But that stuff I mentioned 
is in English. My sytem language is German.

Also, why haven’t I been able to find any strings like these in the 
translation files? :-(

Original comment by almikes@aol.com on 10 Dec 2014 at 6:25

[GoogleCodeExporter]

So, it isn't our job to localise these.  They are Qt generic.
HOWEVER I bet we aren't bundling the qt localisations along with our qt libs.
I'm going to bet I never realised this was a problem because ofc QT is 
installed and managed by distros under Linux.
I'm going to reassign this to unc0rr who can check to see if we are including 
qt_de.qm etc in our release.

Original comment by kyberneticist@gmail.com on 10 Dec 2014 at 6:58