structured logging

Features:

• wrapping slf4j APIs to provide structured key=value pair log messages
• binding & unbinding context to a logger instance which is carried on all log messages
• JSONRenderer to format log messages into JSON
• YAMLRenderer to format log messages into YAML
• mapToObjectArray, objectArrayToMap and mergeObjectArrays helper utils
• support for key-value pairs passed in as arrays items in alternative indices i.e ["key", "value", "key1", "value1"]
• support for LoggableObject interface as a way to pass in log params
• support for key-value pairs passed in as Map<String, Object> entries

v0.4.0

key=value structured logging
binding context to logger instance