[add] solved problem 3 in scheme

- Planned on using a sieve to find trial primes, but abandoned the idea, still a few functions inside 3.scm that are left over from planning the sieve implementation (range, contains?, subtraction, and zip)

- Tests for primes using trial division (also a function that tests for primality using Wilson's Theorem, but it's slow

- Pretty cool sauce stuff
Merge branch 'master' of github.com:mattegan/projectEuler