[6.0.0] Unwanted "print" in ForexDataClient

[MichalMES]

Hello,

Our company just met an issue with your newest v6.0.0 library.
There is a redundant print used in getQuotes() method. This resulted in malformed API response in our application. (debugging-relic perhaps?)

php-forex-quotes/lib/ForexDataClient.php

Line 192 in ab8951a

print("Here pairs". strlen($pairs));

Our walk-around for this bug was to cut off buffered output:

ob_start(); 
$result = $client->getQuotes(); 
ob_end_clean();

... but it is kind of dirty way. We hope that you could clean it up so we all can have a little more pretty code. :-)

Thanks in advance!
Kind regards,
Mike