Bug Fixing, Optimization and File Arrangement

- [Bug Fixing] To support machine with only one device per platform.
- [Bug Fixing] Requirements to run on Windows 7 in which NumPy and
matplotlib functions and data types need to be specifically assigned.
- [Optimization] Add new function called run_par_pL_rC_opt which
organized one parameter of neurons per array instead of combining all
parameters of all neurons in one array.
- [File Arrangement] Move additional file of LifNeuron notebook into
LifNeuron directory that can be used to store image files in the future.
- Collect execution time with 50,000 neurons. Previously only up to
10,000 neurons.