add ipynb checkpoints dir to gitignore
add note about Hack product advertisement
update note about Hack button
compress large data file
social networks RST
per RST, renamed rev_geo to gis_tools, updated README, and edited stderr statment in rev_geo.py
updated README
updated ipynb
updated README and fixed a few typos in the topic modeling lesson.
created content for bash-201 README
updated links for new directory
updated headings
updated headings
updated headings
updated headings
updated headings
updated headings
updated headings
updated indent
fixed typo