Added schema v1.0.2 to achieve this - may need to make further changes.
Modified error handling in data_file_validator to give better errors for this case.

Fixes #30

Fixes #26

Fixes #25

See #23

As we're now checking for more complex version numbers I've added the
'packaging' package to parse and compare for us, and modified the
Validator to use `self.schema_version_string` for the string version, and
`self.schema_version` for the parsed packaging.version.Version object.

Fixes #24

Fixes #27

Additional resources is a minor change rather than bug fix.

 * Hides validators that are for internal use.
 * Fixed argument passing to validators so that old schemas work
 * Added class level docs

This aligns things with the hepdata code.

For use by main hepdata app, so it can preload the allowed remote schemas.

Also made custom_data_schemas in DataFileValidator an instance variable
so it's clear which schemas have been loaded for which validator.

Tests add checks for previous schema change as well as checking for multiple errors

Follows pattern previously used for our own data schema but now works
for submissions and remote schemas.

Also do all further checks even if there's been a previous error, to ensure
all errors are returned.

Also added some valid expressions with - to tests to ensure they are
allowed

 * Rename zipfile to archive in parameters/docs
 * Allow .yaml.gz files as single file archive

… the submission schema

Fixes #34

Added test for this case.