In an effort of ensuring consistent code style in test files as with
the "production" source code, we should run eslint as part of the
`$ npm test` script as well.

Most of the related fixes was done by `eslint` using the `--fix` argument.

Only special configuration tweaks for tests compared to the other
source code, is to allow functions declaration without names. The
rationale for allowing that in tests, is that the important reason we
have them in the source code (proper stacktraces) aren't as important
in test files.

parse method

Pull requests #643 and #664 together fix the issue reported in issue #617, but the change in behavior is causing semvers concerns. See issue #669. Therefore, roll back #643 and #664 and later reintroduce in next planned major release (v3.0).

Fixes #669

Resolve issue #663 and add test.

Fixes #274

Fixes #267

Fixes #247

Text tokens now accurately reflect their content's exact position
in the original template.

Fixes #187

- Cleaner separation of responsibilities in the code between
  scanning, parsing, compiling, and rendering functions.
- Much faster