added Request/Response classes for printing labels
added PrintLabel capabilities for ParcelForce and P4D, though P4D implementation is a stub, and ParcelForce's isn't complete
Merge branch 'develop' into parcelforce-labels
removed credentials reference
Merge branch 'develop' into testdata
fixed bug in UnknownMethodException, added new Exception for arguments that are passed in that don't meet some criteria
changed email address for p4d request to my email
print label functionality now working for valid requests with ParcelForce
added a ValidationIntegrationTests which checks all the plugins validation
updated gitignore
Merge branch 'develop' into parcelforce-labels
updated bond-dependency-injection dependency version to 'dev-develop'
Merge branch 'composer-update' into develop
Merge branch 'develop' into parcelforce-labels
fixed bugs
fixed bugs in local validation
removed a validation test
relaxed the constraint that all couriers had to be feature complete
Merge branch 'parcelforce-labels' into labels
Merge branch 'p4d-labels' into labels