Lisp "Hello World"

Created hw1.l with a hello world program in Lisp

Updated README to warn users of system-dependant sections of hw1.l
they will need to change in order to run the script on any other
system.
Implemented foo(x)

Implemented the function foo(x). If x is a non-integer, foo(x) is nil.
If x <= 1, foo(x) is 1. Otherwise, foo(x) = foo(x - 1) * (x / 2).
Added (quit) to hw1.l

Added a call to (quit) to ensure there are no ghost list processes
left running.
Implemented sigsum(L)

Implemented the sigsum(L) function. This function finds the sign of
each list member (1 or -1) and sums them. Non-numbers and 0 values
are ignored.
Implemented squaredevens(L)

Implemented the squaredevens() function, which accepts a list and
returns a list the same length as the passed list. For each index,
if the original item is an even integer the new item is that value
squared. Otherwise, it is NIL.

Reformatted source file for easier reading.
I Dunno LOL ¯\(°_o)/¯
Stuffs happened. You don't want to know. Trust me.
Merge branches 'develop' and 'master'