FakeVim: Remove unneeded qualifications

Mostly done using the following ruby script:
Dir.glob('**/*.cpp').each { |file|
  next if file =~ %r{src/shared/qbs|/qmljs/}
  s = File.read(file)
  s.scan(/^using namespace (.*);$/) {
    ns = $1
    t = s.gsub(/^(.*)\b#{ns}::((?!Const)[A-Z])/) { |m|
      before = $1
      char = $2
      if before =~ /"|\/\/|\\|using|SIGNAL|SLOT|Q_/
        m
      else
        before + char
      end
    }
    if t != s
      puts file
      File.open(file, 'w').write(t)
    end
  }
}

Change-Id: I41dd2d402b2f5e7c677ddd461a0eeb1c28d98c35
Reviewed-by: hjk <hjk@theqtcompany.com>