numexpr: new package, version 2.4

Description from the numexpr project page [1]:
> Numexpr is a fast numerical expression evaluator for NumPy. With it,
> expressions that operate on arrays (like "3*a+4*b") are accelerated and use
> less memory than doing the same calculation in Python.

I am adding it, because it is a dependency of the pytables package.

[1]: https://github.com/pydata/numexpr
hdf5: Add zlib as optional dependency

This adds addition compression modes to the hdf5 library.

I am adding this, because pytables depends on it.
szip: Fix source hash

The hash code of the downloaded source tar-ball was not identical to the one
specified in the nix-expression. This commit fixes that problem.
hdf5: Add szip as an optional dependency

This adds additional compression modes to hdf5.

Note: The szip license may not be compatible with everyone's use case. Hence,
it is an optional dependency.
hdf5: Update to 1.8.13
tables: add new package, version 3.1.1

From the project page [1]:
> PyTables is a package for managing hierarchical datasets and designed to
> efficiently and easily cope with extremely large amounts of data.

It offers read/write access to hdf5 archives through a hierarchical interface.

I am adding it, because pandas depends on tables for hdf5 read/write
functionality.

Note: The name is a bit of an issue. The project is called pytables, whereas
the python module is simply called tables. I chose to name the nix-expression
tables for consistency with the source-tarball and the module name.

[1]: http://www.pytables.org/moin
pandas: Update to 0.14.0
Merge pull request #3056 from aherrmann/pr_tables

Python module tables