Move reading of configuration out of EnvironmentParamsContainer global scope

Reading the configuration at EPC instantiation (env_params) allows additional
configuration files to override default-scheduler-host.

Also added reading of default-scheduler-port from configuration for consistency.

Change-Id: Idf68ed7b21d3ae65dd233587eaf284df2fa6fcf7
Merge pull request #343 from edwardnewett/master

Move initial reading of configuration out of global scope