A local class is set with:
$ yadm config local.class cls1
More classes can be added with:
$ yadm config --add local.class cls2
$ yadm config --add local.class cls3
Any of cls1, cls2 and cls3 can be used in an alternate condition.
For templates, the existing variable yadm.class/YADM_CLASS is set to
the last class (i.e. cls3) to remain compatible with how it works
today and with what the following command gives:
$ yadm config local.class
For the default template processor there is no explicit yadm.classes
variable. Instead a yadm.class condition will check against all
classes.
For the other processors, a new template variable YADM_CLASSES will be
set to all classes separated by newline. For jinja2 templates a class
can be checked with: {%- if "cls" in YADM_CLASSES.split("\n") %}
For esh templates the logic is a bit more complex, but it is possible
to do.
Fixes#185.
Instead of duplicating the permissions on the temp file, the permissions
are duplicated on the output file directly. If the output file exists as
read-only, it is made writeable first.
There are some environments which don't allow the mv to work if the file
itself is read-only.
