Merge pull request #15 from ag-csw/master

pull
Merge pull request #16 from ag-csw/master

Changing catalog DTD version to 1.0
Merge pull request #17 from ag-csw/master

Added traversal of referenced include directly after importation
updated expected results
Merge pull request #18 from ag-csw/master

issue #12
changing CL namespace
taking out importHistory.pop
adding missing namespace when searching for content of a titling
also cleaning up cloning when an include is created
unit test - checking for missing include files
expanding unit test to check contents of results files and catalog
updating expected  results in order to pass unit tests
resolving issue #27
moving the catalog and includes structure into Corpus, and making the resultsDir a parameter

The Corpus constructor takes a parameter for the directory, and constructs in Includes and XMLCatalog as well as reads in documents.
The Includes constructor reads the files in a local includes directory, but must reconstruct the Titling (issue filed on this).
The XMLCatalog constructor reads in a local catalog file from disk.
The Includes and XMLCatalog classes now have their own write methods
Case Q added to test loading the results corpus from case G.
typos in case P
case Q modified for checking errors in consistency
major refactoring of Includes to use the content of titlings
Includes / Catalog now use the relative file path, including extension as key / value, resp.
code cleanup
exception handling and extracting some methods
using Corpus methods to clean up code
case R added showing a use of XInclude directives to assemble a CL corpus from external sources.