First check-in
Add stub for dependencies checking when validating

Start adding dependency checking between columns and add a new
config file for testing that. Add more tests for the validation
plugins.
Validate "if-then-else" constraints on columns
Add working "one-of" relationship, plus tests
Add more validation and tests

The ontologies can be fairly large (160Mb for GAZ) so we now
cache them as hashes instead of using system grep for every row.
Add new test data/tests and fix bugs accordingly
Add metadata to keep dzil happy
Add module to download and cache files for tests
Add new files for testing ontology validation
Change the behaviour of the validate method

Now returns 0/1 if the file is invalid/valid, rather than throwing
an exception.
Add more tests and a wrapper script
Create README.md
Add piwik analytics
Add a bit more detail to README
Tidying up after a git cock-up

Conflicts:
	.gitignore
	README.md