External files are cached

[KrekkieD]

I was referencing a custom schema through https, but had an invalid certificate (required an exception). As a result, it threw a certificate error. But when changing all references of https to the http equivalent, the error kept appearing. Adding a '?' at the end of the id and $schema did not change the error (still cached somewhere). I had to rename the schema from schema.json to schemas.json for the change to be picked up.

This was on the instance validation part of http://json-schema-validator.herokuapp.com/index.jsp