Lesson1 Draft
Merge pull request #6 from barbagroup/gil

Fix typos and clarify explanations in the first section
Merge pull request #9 from barbagroup/2ndED

2nd edition, fix the issues #4 #5 and #7
Lesson 2 code modification
1st ed of Lesson 1
README, add Lesson 1
Merge pull request #10 from barbagroup/piyueh

Merge for Lesson 1