Updating ``dpp-msprior`` mac executable.

Updating the mac binary for ``dpp-msprior``. It was built as a universal
binary from version 0.2 of ``dpp-msbayes``. Changes were made to
dpp-msprior in this version to prevent the reporting of theta values of
zero, which would cause ``msDQH`` to crash.
Updating `dpp-msprior` linux executables.

Updating the 64-bit and 32-bit binaries of `dpp-msprior`. These binaries
were compiled on a rocks cluster from version 0.2 of `dpp-msbayes`. This
version made changes to `dpp-msprior` to prevent the reporting of theta
values of zero, which caused `msDQH` to crash.
Incrementing package version to 0.3.0.

Upating package number and ``CHANGES.txt`` accordingly.

The only change is the new version of the ``dpp-msprior`` executable.
However, this change will affect results (albeit slightly), so bumping
from 0.2.x to 0.3.
Merge branch 'release-0.3'