CodeSnip Old Code (SVN)

* Rationalised TDataStreamWriter code, removing redundant methods.
* Changed Unicode only TDataStreamWriter methods that write strings to specifically use UnicodeString type.
* Revised and completed commenting of TDataStreamWriter.

* Replaced TDataStreamReader string type with Latin1String.
* Deleted TDataStreamReader from UDataStreamIO.pas.

Modified UDataStreamIO.pas for Unicode compatibility.
* Changed string type read/written to TDataStreamString which is defined as AnsiString on Ansi Delphis and Latin1String on Unicode: i.e. single byte strings on all compilers.
* Provided overloaded write string methods that take Unicode strings and convert to Latin1.
* Provided methods to convert strings to byte arrays for writing.

Merged trunk changes r401:429 into the delphi2010-port branch.

Development branch to make project compatible with Delphi 2010.