CLC-3201 - Fix README

https://jira.media.berkeley.edu/jira/browse/CLC-3201

* Fix links
* Fix numbering (not only 1)
* Fix paths (use quotes)
* Set appropriate language for code (`bash` / `erb` / `html`)
* Make sure that people can copy/paste most code in the terminal. (E.g. comments in bash should have `#` in front of them)
* Remove sourcemaps - since we actually don't support it