Feature/issue 331 error message 1 indexed

#### Summary:

Error messages for vectors and matrices are 1-indexed instead of 0-index.

#### Intended Effect:

This affects the error messages for models. Messages are 1-indexed instead of 0-index.

#### How to Verify:

There are unit tests that show the new behavior.

#### Side Effects:

Added a new trait that controls whether the run is 0 or 1 indexed. For now, it's set to 1.

#### Documentation:

Not sure if this is highlighted anywhere in documentation already. Should we bring this up?

#### Reviewer Suggestions:

Bob, want to take a look?