Remove obsolete function sorter
Merge pull request #739 from ifduyue/ifduyue/remove_obsolete_func_sorter

Remove obsolete function sorter
Fix: logger_class can be undefined.
Merge pull request #741 from ifduyue/logger_class_bug

Fix: logger_class can be undefined.
Move setting of environmental variables before preload_app start.

Move setting of env vars from Arbiter.start to Arbiter.setup so that they are available during application start up when 'preload_app' is used.

Closes #735