tr()-Fixes for 2.6.

- ProjectExplorer::Profile should appear as 'Target' in the UI.
- Fix messagebox title capitalization
- Fix Q_DECLARE_TR_FUNCTIONS to contain fully qualified class
  names, add where applicable to replace
  QCoreApplication::translate().
- Introduce message utility function for the commonly used
  'No tool chain set up for this profile' message to
  ToolChainProfileInformation.
- Introduce message utility functions related to adding files
  to version control to VcsManager to be shared by QmlJsEditor.
- Fix typos.
- Remove QObject::tr(), QCoreApplication::tr().
- Do not translate diagnostic console warnings of
  QmlProfiler.

Change-Id: I6cee717a504796ef39f6eae58f552c5c8630adf3
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>