Minor cleanups
Reinforce code style take 1

- Use 'x' for instance names consistently
- Use 'as self' to refer to instance names in constructor declarations
Reinforce code style take 2

- Module functions are camelCase
- Type members are PascalCase
Reinforce code style take 3

- Remove unused parameters (which have '_' prefix)
- Type annotation should use ': ', not ':' or ' : '

Address #86