Splitting Function Currencies
- Adds a function to split a string into the various monetary components.
- Makes the MoneyParts a full type with all parts ensured to be correct.
- Adds extra unit tests for the direct amount assignment constructor.
- Makes explicit that the code coverage is running under fedora.
- Makes all objects const in the money unit test that can be.
- Enables C++ 17.
Closes #32 (closed)