Moved all source files into ./src

Since we aren't actually making a library, we can
happily have all of the files live together.

I also renamed battle to main
Added basic makefile to decrease typing for builds
Fixed warnings for non-void function not returning

warning: control reaches end of non-void function [-Wreturn-type]

Basically these methods don't actually return an integer
so they should be void.
Merge pull request #2 from willluongo/more_ideas

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