Add Lazy<Regex> for performance gain in Hex variables
Add Lazy<Regex> for performance gain in Hex variables

To avoid the creation of the Regex in the first use of the class is
better to instanciate the Regex in the first use of the EncodeHex method
(if never called so no Regex is created or compiled)

More info about RegexOptions.Compiled
http://stackoverflow.com/questions/513412/how-does-regexoptions-compiled-work

ullmark/hashids.net,ullmark/hashids.net