initial commit config_file

added load_absent_file
added cf.commit
added cf.load_populated_file
cf takes initial properties object
cleaned up config read

will automatically read file_path if initial_properties not provided at
init;
will not change .props if corresponding file path does not exist  (or
any error)
sp and sc creation is now async
Merge pull request #2 from hexparrot/config_file

Config file