Added MCNP PTRAC readout support.

Added a class to read MCNP PTRAC files, and a shell script to easily
dump a whole PTRAC file into a HDF5 table.
2 Bugfixes in PtracReader

PtracReader now extends object, and its constructor opens the proper
file.
Merge remote-tracking branch 'upstream/staging' into staging
Bugfixes and test cases for MCNP PtracReader
Fixed PtracReader, added tests for 8 byte MCNP
Switched ptrac script to argparse

(with an implementation of argparse included as a Python < 2.7 fallback)
Some minor updates
Merge branch 'staging' of github.com:jdangerx/pyne into jdx-staging
updeated endf example
Merge branch 'staging' of github.com:cbrachem/pyne into cbrachem-staging
some cleanup for ptrac_to_hdf5
fix for finding python libs
FindCython doesn't find local cython.

Detect the cython executable in the same path as the python
executable used in a local installation.

Reported by Paul Romano.
Update FindCython.cmake from upstream (thewtex/cython-cmake-example)
Merge pull request #123 from thewtex/CMakeCythonExePath

FindCython doesn't find local cython.
adding files to be used for test_meshtal.py
adding files to be used for test_meshtal.py
added easy meshtal input file and easy meshtal meshtal file
Merge pull request #125 from elliottbiondo/mesh

Test meshtal files (and corresponding MCNP inputs).
Merge remote-tracking branch 'upstream/staging' into mesh

This is an update to staging. Any future PRs will be rebased first to avoid this.