Re-write QuantEcon.py in pure python WASM compatible

[kp992]

While working on the #143, I noticed that several lectures are using quantecon in intro series:

lecture-python-intro % git grep 'import quantecon'
lectures/_static/lecture_specific/inequality/data.ipynb:    "import quantecon as qe\n",
lectures/eigen_II.md:import quantecon as qe
lectures/input_output.md:import quantecon_book_networks
lectures/input_output.md:import quantecon_book_networks.input_output as qbn_io
lectures/input_output.md:import quantecon_book_networks.plotting as qbn_plt
lectures/input_output.md:import quantecon_book_networks.data as qbn_data
lectures/markov_chains_I.md:import quantecon as qe
lectures/markov_chains_II.md:import quantecon as qe
lectures/networks.md:import quantecon as qe
lectures/networks.md:import quantecon_book_networks.input_output as qbn_io
lectures/networks.md:import quantecon_book_networks.data as qbn_data

As a solution, @mmcky and I decided to re-write a minimal pure python package of QuantEcon.py that is WASM compatible. This issue is for tracking the progress of the package.

• qe.MarkovChain
• qe.random.draw
• qe.DiGraph

[kp992]

@mmcky Can you please help in setting a new repo for this package under QuantEcon and I can start porting some code from QuantEcon.py