Multiple exception types

[alecsammon]

Currently the library throws \Exception objects. This would be much nicer if we threw custom exceptions that showed more clearly what the error is. I.e.\Raml\Exception\ParseException

[titomiguelcosta]

I don't mind working on this one, simple and add great value in the end.

[brendo]

This would be great :)

[alecsammon]

If you got a chance @titomiguelcosta that would be awesome 👍

[titomiguelcosta]

it is on me, expect a PR on the weekend

[alecsammon]

you are a ⭐