util: Add isCalpha, get_registered_domain, and extract_domain functions
util: match_domains function
Reject redirection across different registered domain names (can be disabled by appending #redirect to pool URI)
get_registered_domain: Return full IP for raw IP addresses, so they can at least redirect to the same IP
Merge branch 'redirect_xss' into bfgminer

Conflicts:
	util.h