Revert "add two problems rom rosettacode"

This reverts commit b165bd474837bbcde9e51a67dce9577882d1fb0b.

Signed-off-by: amineorion <amineorion@gmail.com>

Conflicts:
	examples/rosettacode/hailstone.nit
	examples/rosettacode/hamming_number.nit