LEARNCLJ-8: added repl lecture for channels that will be part of lecture 6
Merge pull request #13 from mateoconfeugo/channels

LEARNCLJ-8: added repl lecture for channels that will be part of lecture...
LEARNCLJ-8: added the macro lecture code and notes
Merge pull request #14 from mateoconfeugo/macro-channel-lecture

Macro channel lecture