fix (Profiler.php) use getTrace() instead of getTraceAsString() to gain much more usefull information
refactor (Db.php) move profiler creation after connect and add profiler.class config variable to make possible to replace default implementation
feat (Statement.php) new property profilerId to save profileId of current execution
fix (Statement.php) all error checks rewritten from !$condition to $condition === false to make code more error proof
feat (Profiler.php) return profile id in start()
feat (Db.php) change return value of startProfile to value returned from profiler
fix (Db.php) all error checks rewritten from !$condition to $condition === false to make code more error proof