Also:
- Use {}-style list initialisation for SourceLocation construction
- Introduce new system includes
- Changes the API of the Scanner to take source as value (with move) as opposed to as a reference
This commit introduces ErrorReporter, a utility class which consolidates
all of the error logging functionality into a common set of functions.
It also replaces all direct interactions with an ErrorList with calls to
an ErrorReporter.
This commit resolves issue #2209
