Start sieve algorithm

sieve.py

@@ -0,0 +1,9 @@
+# Sieve of what'shisname, in python
+
+def sieve(to):
+    """Construct a sieve of Erastowhatsit up to the value of to; return all
+    primes below this number.
+    """
+    # Need to find out how to initialise vector/array/list whatever
+    # numpy.zeros
+