当qml文件添加到qrc文件中，实现internationalization(国际化)

lupdate test.pro只检测 SOURCE 和 HEADER中的文件，当qml文件添加到qrc中时lupdate test.pro时不能被检测到，这时需要手动添加qml文件或者ts文件告诉lupdate时检测，

具体步骤，example:

test.pro文件

TRANSLATIONS += \
　　fr.ts \
　　ch.ts \  //　这里是需要生成的翻译的语言生成的ts文件

lupdate_only{
　　SOURCES += \
　　　　test.qml \
　　　　common/*.qml \
}

然后lupdate test.pro就OK了

Usage:
     lupdate [options] [project-file]
     lupdate [options] [source-file|path]... -ts ts-files
 Options:
     -help  Display this information and exit.
     -noobsolete
            Drop all obsolete strings.
     -extensions <ext>[,<ext>]...
            Process files with the given extensions only.
            The extension list must be separated with commas, not with whitespace.
            Default: 'ui,c,c++,cc,cpp,cxx,ch,h,h++,hh,hpp,hxx'.
     -pluralonly
            Only include plural form messages.
     -silent
            Don't explain what is being done.
     -version
            Display the version of lupdate and exit.

lrelease test.pro生成qm文件

 Usage:
     lrelease [options] project-file
     lrelease [options] ts-files [-qm qm-file]
 Options:
     -help  Display this information and exit
     -compress
            Compress the .qm files
     -nounfinished
            Do not include unfinished translations
     -removeidentical
            If the translated text is the same as
            the source text, do not include the message
     -silent
            Don't explain what is being done
     -version
            Display the version of lrelease and exit