SVN: Always use internal diff command

This unbreaks svn diff views for users with custom diff
commands set up in their subversion configuration.

Task-number: QTCREATORBUG-9303
Change-Id: Ie3a726f08ad39770b63e2432755467df429067f8
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
Debugger: Adjust wording of symbol server dialog.

Change-Id: I7bbfbe2a95ddb6bcfa8fcb3aca8fc9a602c20bea
Reviewed-by: Robert Loehning <robert.loehning@digia.com>
Reviewed-by: David Schulz <david.schulz@digia.com>
Squish: Update handleDebuggerWarnings()

Change-Id: Ifd0a9270f84abe15603cbf80ef18eb7450436c74
Reviewed-by: David Schulz <david.schulz@digia.com>