Fix a regression introduced with Python 3 port -- JSON deserializer
should check for basestring rather than str when deciding whether to try
to decode a custom type.
Add a cpu_mask type to allow for users to use a consistent way of representing a
cpus mask with properties to provide conversions between the various required
forms. The mask can be specified directly as a mask, as a list of cpus indexes
or a sysfs-style string.
Also add support for the type to be serialized/deserialzed for the json
and yaml serializers.
"params" is interpreted differently in section vs workload entires in
the agenda; previously, this was handled in the generic entry
construciton function by examining the ID prefix of the entry to
distinguish between the two.
This is unreliable as the user may specify their own IDs that won't have
the expected prefixes. To handle this, the "params" alias resolution for
sections is now handled in section specific part of entry processing
(workloads are handled autmatically because that is the default for
the corresponding JobConfig config point).
Changing the way target descriptions work from a static mapping to
something that is dynamically generated and is extensible via plugins.
Also moving core target implementation stuff under "framework".
