Updates for 4 classes

Today I have updated the following classes:
- FTPConnection
- SMTPConnection
- SQLSession
- TCPConnection

The first two have been ported to extend from TCPConnection. These classes also utilize the new read-functions of TCPConnection, which offer more controlled reading from the stream.
The new version of SQLSession is a recode and thus is not compatible with earlier versions. The good news is that the new version now works again on PHP4, and that now $_SESSION can be used, as the class works with the normal sessions, instead of storing the data directly into the object.