Almost Perfected Makefile

Now when you run make, the Makefile will first create the StudyHelper
platform program, titled "StudyHelper" (with extension .exe on Windows).
Then, the program will make all "lesson" executables by finding the
subdirectories in src and going through each subdirectory and building
it into the name of the subdirectory plus the possible extension.  From
there, it will copy all lessons and stuff.  I will test this on Linux
tomorrow, and will likely make some changes, like making the lesson
executables start with "Lesson" so that Linux can delete them in cleanup
(as Linux executables don't have extensions).  It is almost perfected
right now, however.