* The DataReceived hook gets a position argument, making it possible for
listeners to handle out-of-order data (from two range requests at
different positions, for example)
* Adjust HaikuDepot (only user of the API in our sources)
* Add a copy constructor to HTTPRequest that copies the relevant
parameters from an existing request. Makes it easy to repeat a request
with a different range. Could be useful for restarting downloads, or
paralellizing them.
* Add SetRangeStart, SetRangeEnd calls to HTTPRequest, no implementation
yet. I'm putting all the API changes in this commit as it needs to be
synced with a matching haikuwebkit release.
* All archs must update to HaikuWebkit 1.3.0. Previous versions are
broken by this.