Store Student ID in long long instead of int

This fixes an overflow issue when having a 10 digit ID. The reason this
is long long instead of just long is for cross-compatibility. If I
recall correctly, long and int are the same size on Windows. And, since
I haven't switched to using things like int64_t, I'll just set it to
long long.
Split release and debug options in Makefile

`make' will build a release version with optimizations, no extra
warnings, and no debug symbols. `make debug' will include these. This
really is for using gdb in Qt Creator, which would behave interestingly
with the optimizations enabled (e.g. skipping a breakpoint and stopping
a few lines later).
Slight cleanup

While debugging I realized there were two variables named the same,
which was somewhat confusing when displaying local variables. Also
slight spacing cleanup.
farthestFromPoint use x+y instead of sqrt(x^2+y^2)

The diagonal distance would occasionally put a corner on some oddly
extruded pixels out the side of a box instead of on the actual corner.
This change will tend toward farther horizontally and vertically, which
should be the opposite corner of the box.
Added Qt Creator project files

I recently started using Qt Creator, after finding out that it was not
solely for Qt development. Unlike Eclipse or Visual Studio, it does not
create a bunch of project files, only two (when not using CMake). So I
thought I'd include them in the project if anybody else uses it as well.