Stronger phone stand

[Fixed scale issue- 4/11/19]
[Added a back piece with a hole for a keychain- 4/11/19]

I used Symbole's design for a foldable phone stand (https://www.thingiverse.com/thing:3544108) and made a slightly stronger version of it. I just tested this and I believe it is a bit more stable, but not by much, so I may continue to edit this and make it even more so. I also got rid of the key chain bit because I wasn't going to use it. I will try to remember to upload a version with the key chain hole.

Note: The 'Boo_pins' file is the same file from the original design. 'SCALED_hinge' is also the same design as the original.

(I also changed the front legs a bit, but it doesn't add any stability)