Environment Variables Modifiers

Added:

• Support for built-in and custom Environment Variables modifiers
• Support for custom mergeTypeOf option
• Support for non-POJO objects, configly will copy class instances as is, instead of attempting to merge their individual properties

Changed:

• Renamed directory option to directories
• Removed standalone directories argument, should be passed via options object
• Streamlined default invocation require('configly')(); -> require('configly');, latter returns parsed config object obtain with default parameters, to access configurable configly instance use require('configly/configure');

Chore:

• Upgraded dependencies