buildenv/osx: add autotools to the build env to avoid Homebrew requirement.
buildenv/osdx: Qt 5.1.0 is out.
buildenv/osx: explicitly build libxar without LZMA support.

Some people have LZMA installed via Homebrew/MacPorts/themselves.
We don't want any outside deps, so disable LZMA explicitly.
buildenv/osx: update Boost to 1.54.0.
manual merge