Update toString() to use late static binding for encoding methods

Change-Id: I470379b8527852d5f36145c88ab05cbb51582103
change validHostTypes to 0x13
Merge pull request #3980 from samsonasik/fix/hosttype

change HOST_DNS_OR_IPV4_OR_IPV6 to 0x13 for $validHostTypes
[#3980] Created new constant

- per @DASPRiD
- evaluates to 0x13 (10011)
- name describes its purpose