% make all
This now builds executable, executable_debug, and executable_profile.
This will allow for easy implementation of the autograder building and
testing student solutions. When a SIG occurs, the AG can then run
valgrind with a debug build, to give improved feedback to students.

Build objects (.o files) are now only created for release builds.
Therefore, any .o file found in the directory will be compiled with -O3
and -DNDEBUG. The other two build targets (debug and profile) are
compiled directly from source to executable. This should prevent any
unfortunate hybrid builds.

Some minor documentation and formatting updates were also made.