Revert "Revert "DynamicBuffer: implement BDataIO""

This reverts commit 747b401e875f19d83508cc39176f4c263182c515.
DynamicBuffer: dos2unix
DynamicBuffer::Write(): Fix return type and semantics
DynamicBuffer::Read(): Small optimization (skip 0 case)
BNetBuffer: Restore semantics after DynamicBuffer -> BDataIO
Revert "Revert "HttpRequest: support gzip and deflate compression.""

This reverts commit 256080b112e417fc4fd2f3f9fcb23485e1b23b42.

With the following changes:
* Adjusted to the BZlibCompressionAlgorithm API.
* Add some error handling.
BUrl: Add missing functionality from support kit BUrl
Remove private support kit BUrl

Use the public BUrl from the network kit instead.
BZlibCompressionAlgorithm: Missing NULL check
BUrl::IsValid(): Replace with a slightly better dummy impl
Copy haikuports/FormatVersions onto the bootstrap image.

* Without it, haikuporter will believe there's a version mismatch
  between itself and the haikuports tree.
Use a specific packager for continuous integration builds.