Create new directories as needed when copying tests from PP repo
Tweak error message for unknown type
Add Decoder-database.t from PP repo
Don't pass -DMISSING_UINT128 to the compiler
Add support for decoding bytes and tweak how utf8 strings are handled

Also added a placeholder for uint128
Ignore .o files
First stab at uint128 support

I still need to make this work when uint128s are byte arrays