Fix ambiguous regexes

The schema contains some ambiguous regexes. This causes Ruby to display warnings like this:
```
warning: character class has '-' without escape: /^[\sa-z0-9-+;\.=\/]+$/
warning: character class has '-' without escape: /^[a-z0-9-]+\/[a-z0-9-+]+$/
```

That's because `-` is a special character within a character group definition (i.e. between []'s). In order to make it clear if the regex intended to use it as a range delimiter or a literal `-`, you are supposed to either escape it or put it as the first or last character in the group. I'm not sure if the first/last trick is universally supported (and it is not mentioned in the limited regex constructs that [json-schema recommends](http://json-schema.org/latest/json-schema-validation.html#anchor6) for broad support) so escaped it.

NB: ResourcesTest.scala:161 is already failing. That is a pre-existing problem.