perform rigorous validation on all API parameters, cleanup redundancy in sanitize.js and validate.js - issue #1526

Signed-off-by: Lloyd Hilaiel <lloyd@hilaiel.com>

fixed check for site parameter, it should be an origin not a domain, and fixed all tests accordingly. Was careful not to screw up the verifier tests that are testing for old parameters to the verifier.

when certifying secondary certs and the user has not confirmed their ownership of the given computer, certify with a short validity period

fix a bug in validation library.  if we find a parameter validation error, don't call the next handler in the onion ring, fail out

break 'checkParams' feature out into a separate file so it can be shared by multiple processes - issue #460