Organized files + updates basic server to handle basic query strings

Create packages for dice and statistics. The files in 'main' package now expect a specific folder structure to pull in those packages.  Followed this to set it up: https://golang.org/doc/code.html

Basically, it expects $GOPATH/src/github.com/Akavall/GoGamesProject, can check your $GOPATH by doing `echo $GOPATH` 

Also, can now pass parameters using query strings in URL (also moved methods to separate paths, so just localhost won't work for now):

http://localhost:8000/dice_roll?sides=10
http://localhost:8000/four_dice_roll?sides=12&rolltimes=3