Merge remote-tracking branch 'sigu-399/master' into add-context-to-error-messages

Conflicts:
	validation.go
update description for jsonContext.go
Merge pull request #6 from tolsen/add-context-to-error-messages

Add context to error messages
Merge branch 'master' of https://github.com/sigu-399/gojsonschema

Conflicts:
	validation.go
added missing jsonContext while merging "subschema dependencies" branch
Merge remote-tracking branch 'sigu-399/master'

Conflicts:
	validation.go