SFTP: Replace incorrect comment about filesize. There is no 4 GiB limit.
Merge pull request #492 from bantu/sftp-large-file-comment

SFTP: Replace incorrect comment about filesize. There is no 4 GiB limit.

* bantu/sftp-large-file-comment:
  SFTP: Replace incorrect comment about filesize. There is no 4 GiB limit.
Merge branch 'master' into php5

* master:
  SFTP: Replace incorrect comment about filesize. There is no 4 GiB limit.

Conflicts:
	phpseclib/Net/SFTP.php