Refactorings to reuse code from Main class.

Extracted parse() and createWritableDocument() methods from Main.
Made utility methods public.
Removed unnecessary throws clause from ReadableData.read().
Calabash class complete

Calabash class now supports two run() methods.
+ run(XdmNode, Input, Output)
+ run(XdmNode, XdmNode): PipelineOutputs
Added methods to format an error message for an XProcException.
Also closed input stream in ErrorMessageRegistry.