Added non_empty parameter validator to validate non-empty strings.
proposal changes settings
added specs
added specs
added specs
style fixes
added some specs
fixed some specs
refactored format and depentend code to new settings style
refactored logger setting
refactored last description
refactored middleware settings
renamed InheritableValue and StackableValues
added a setting on api class level
change in keys to honor symbols
change in params documentation
refactored helpers settings
refactored formatters
refactored parser
refactored error_formatters