Several updates  * Implement range_to_cidr static method  * Throw exception in cidr_to_range for invalid bit lengths  * Enhanced CIDR::__toString to return better IP string based on available prefix  * Allow CIDR::__construct to accept second parameter to handle IP ranges easier
Several updates
 * Implement range_to_cidr static method
 * Throw exception in cidr_to_range for invalid bit lengths
 * Enhanced CIDR::__toString to return better IP string based on available prefix
 * Allow CIDR::__construct to accept second parameter to handle IP ranges easier

lifo101/ip