Better validation for <resource> media

[sschiavoni]

Original issue 32 created by yuch@google.com on 2012-10-03T06:53:06.000Z:

What steps will reproduce the problem?

• The validator doesn't validate that the audio/jpg files linked in the <uri> or < derefUri> tags actually exist.

What is the expected output? What do you see instead?

• The validator should display a warning

What version of the product are you using? On what operating system?

Please provide any additional information below.

[sschiavoni]

Validating the external resource was discussed and marked as unfeasible. Validation of the base64 resource was added in the last release.