Make the README more concise

[kjorg50]

While the README.md file contains lots of great information, it has a little more than what is usually needed in a typical README.md file. For example, the code examples under "Documentation" contain full classes, where instead it might be more useful if only certain portions of these classes were displayed, with descriptions of why these specific sections are important.

Additionally, the current screenshots show the entire gameplay sequence of the games. It might be preferable to simply display an example of what each different game looks like.

When choosing what to update in the README, don't simply throw existing documentation and/or images. Consider adding them to the wiki:

https://github.com/UCSB-CS56-Projects/cs56-games-rock-paper-scissors/wiki

because this is the appropriate place to put more detailed documentation. Then, just put a note in the README saying that more info can be found in the wiki

~estimated 200

[athielk]

F16 OK (100 pts)

[lanthony159]

F17 OK (100 pts)