Added all files

- First version of Python test framework for running external program
commands with subprocess.popen
- the main framework module is external_program_test_framework.py
(worry about a better name later)
- assert_variable_type.py is a helper module for making sure a variable
is of a certain type or types, returns True or raises a ValueError,
helpful for argument checking
- nstream_readerwriter.py is a modified version of the module from
http://eyalarubas.com/python-subproc-nonblock.html, allows
reading/writing of output stream in a separate thread from the
subprocess to allow live logging without impacting execution time (i
think)
- run_subprocess.py is helper module to run a subprocess with popen and
returns the process and execution time measuring using the timeit
module. require the nbstream_readerwriter.py module
- all the separate helper module can be reused for other projects as
well