Shelter

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+ Added ``app_settings_handler`` hook.

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+ Semantic versioning
+ ``settings.INIT_HANDLER`` can be either string or list of strings
+ Service processes are started only in `runserver` command
+ ``Config.command_name`` contains name of the current management command
+ Clean code, fixes
+ Sphinx documentation

Upgrade from 1.1.x


+ Constants ``shelter.core.processes.SERVICE_PROCESS`` and
``shelter.core.processes.TORNADO_WORKER`` are moved to
``shelter.core.constants``.
+ ``Context.initialize_child`` keywords arguments are changed.
+ Majority of ``shelter.core.commands.BaseCommand`` control attributes are
removed, only ``settings_required`` is now available.
+ ``context`` and ``interface`` are not passed as keywords arguments into
``shelter.core.web.BaseRequestHandler`` constructor.

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+ Fixed exiting of the main process when children exist and error is occurred
+ PEP 396 module version info

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+ Fixed constructing list of the sockets in devserver command

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+ Add ``initialize_child()`` method into ``shelter.core.context.Context``
+ Always restart worker when it stops
+ Interfaces now support UNIX sockets for communication

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+ *devserver* and *shell* management commands now start service processes
in threads.
+ Add ``initialize()`` method into ``shelter.core.processes.BaseProcess``
class.
+ Some minor improvements.