Fix wrong description.

modified:   sect-1-3.md
Merge pull request #6 from toshio-yamada/spike

Fix wrong description.
Add chapter 1.4
Merge pull request #7 from Otsuka-iOS-Study-Club/add-chap-1-4

Add chapter 1.4
modify readme: add link to section 1-4.
Merge pull request #8 from Otsuka-iOS-Study-Club/edit-readme

modify readme: add link to section 1-4.