Start work on a packed BCD type limited to a single word
Test the previously implemented code

Redifine front to mean the Most Significant Digit and back to
mean the Least Significant Digit.
Add some constructors
Add some more immutable usage
Name the constants consistently
Make opSlice work with const/immutable
Add opEquals and opCmp
Add toHash
Make sure the implicit this pointer is not referenced in the tests
Improve the opEquals testing
Add opAssign
Add an implicit conversion to the type "ulong"
Extend the numerical constructor to accept all built-in numbers
Improve the function annotations
Implement addition for two packed BCD numbers
Add binary addition
Allow writefln to be used in outer unittest blocks
Use standard, explicit assert style in test blocks
Add toString
Add opOpAssign