placeholder text into id and secret fields, added xrate method in client to fetch latest exchange rate, fixed https bug
Merge branch 'master' of https://github.com/GoCoin/gocoin.PHP into gocoin-php-api-sml

Conflicts:
	examples/login.php
	examples/user.php
	examples/user_update.php
fixing conflicts
Merge pull request #5 from GoCoin/gocoin-php-api-sml

Gocoin php api sml