Fix: markdown typo - extra`
Merge pull request #128 from rcorp/markDownTypo

Fix: markdown typo - extra`
Fix: type - summarize
Fix typo: continuing
Merge pull request #129 from rcorp/typoInScopeCh1

Typo in  scope & closures ch1
Adding link to Shane Hudson's Foreword
types+grammar: adding lots more content to chapter 1, finally