Config-loader instead of validating a config file which is required throughout now modifies it's own exports, becoming the central config store throughout Ghost.
Prefer "configFile" and "config" variable names in config-loader. Towards #1110.
Revert Gruntfile.js to not permitting forin.
Observe GHOST_CONFIG environmental variable

Ghost will check, if no configuration file is passed in as an argument, the environmental variable GHOST_CONFIG: if found, it will use this in it's attempt to configure itself before onlining.
Remove globalConf temporary variable.
Drop assignConfig custom code in preference for standard library code _.extends.