add missing chapters to epub

Update anti-patterns.md

Re-arranging things after some feedback

remove things from hello world, fixing quii#399

add links to anti-patterns chapter

Brief intro to comments and tiny formatting update. (quii#409)

* Add intro about comments after their first mention

* Add formatting to string for consistency
* Specific line has int highlighted just before it as well

typo

better sources

revisiting http handlers

Context reader (quii#321)

* context reader chap

* some corrections, less waffle

* Update README.md

* making naming consistent with chapter heading

* add link to context reader to gitbook

maths