Ccpstencil

Changed

- `FileRenderer` (and thus `DirectoryRenderer`) now use `\n` line endings in the
resulting file. This should probably just be an option with the default being
to preserve the line ending format of the template file, but since this is
being used to render files that should run on Linux and apparently incorrect
line endings mess up the shebang reading and sh*t like that so I'm applying
this "sh*t fix" for now.

Added

- A new `DirectoryRenderer` and `DirectoryTemplate` to render entire directories
of templates in one go
- Support for `{% skip_if %}` and `{% setfilename %}` tags to control directory
names and skipping by adding them to a file called `__stencil_meta__` placed in
any directory in a `DirectoryTemplate`
- The ability to run directory rendering via command line with the `-d` flag

Added

- A new `{% setfilename %}` tag where you can set the desired filename of the
rendered file dynamically in the tags body with normal template code e.g.
using the template context

Changed

- The `FileRenderer` can now define a directory as output location which will
result in the rendered file to be the same as the input template file name
(if any) unless set explicitly via the `{% setfilename %}` tag.

Fixed

- FileRenderer was hitting an infinite loop
- Added dynamic path extension to include cwd to enable `${__PY__:...}`
injecting from project roots

Changed

- Bumped the version requirement of Alviss to 3.3 to get support for the new
`${__PY__:...}` expressions in order to inject module versions into Alviss
contexts for CI/CD manifests

Added

- New Extension that adds a `{% skip_if %}` tag where you can insert any
condition (e.g. checking the Context) and if it evals as True, a
`CancelRendering` exception is raised and caught by the Renderers causing
them to silently just skip rendering that template.
- The `StringRenderer` returns `None`
- The `StoutRenderer` prints out nothing
- The `FileRenderer` doesn't create an output file
- Added unittests for the `{% skip_if %}` tag