#37 BinaryData constructor, bool operator (same as previous patch), handling <string/> (similar to data patch), and handling time correctly.

[Dan Landers]

This should have several improvements:

1. Adds a BinaryData constructor to XmlRpcValue class (header).
2. Adds a bool assignment operator (similar to a previous post) to XmlRpcValue class (header).
3. Handles <string> empty string in XmlRpcValue class (source).</string>
4. Correctly coerces time to and from the ISO string format to C's tm struct.