[x] Added frontend passing of backend errors for login and signup.
[x] Do a bit of cleaning/modifications to remove some pesky eslint warnings and to get rid of memory leak warnings (such as from trying to setState when component did not mount yet).
Result: the dev console is mostly error free (except for the http error codes thrown from the back end, but that's intentional!)
Quick changes:
Result: the dev console is mostly error free (except for the http error codes thrown from the back end, but that's intentional!)