sets note values
withdraw implemented
NoteUnavailableException implemented
InvalidArgumentException implemented
code refactored
empty set when null is given
improve tests methods and add other test to withdraw note unavailable
add other test to withdraw note available
withdraw refactored and add getNotesAvailble method
create docblocks
created an Account and Machine look for Account balance
repository restructured
scrutinizer coverage configuration
fix composer.json
remove codes from Machine and create a NoteCollection
fix code style