Debugger::barDump() can be temporarily disabled/enabled

[forgie1]

To prevent overcrowded dump, barDump can be temporarily disabled/enabled on demand.

eg:

function one()
{
    ...
    \Tracy\BarDump();
    ...
}

\Tracy\Debugger::$barDumpOn = false;
foreach ($many as $row) {
    one();
}

\Tracy\Debugger::$barDumpOn = true;
one(); // only this needs to be barDumped