Add flag to chidley to include XML in generated code instead of reading it in

[gnewton]

For small amounts of XML, and to allow cutting-and-pasting of a complete working (chidley generated) code into the Go Playground http://www.codata.info/canada/ , allow for the inclusion of the file XML as a string.

chidley:

• flag to allow this
• update templates to handle this
• warning for too large XML (> how much?)
• put XML string at end of generated code?

generated code:

• Need to modify to handle this
• flag needed