Fix typos

"factor" -> "factory"
"descired" -> "desired"
Merge pull request #596 from cubranic/patch-1

Fix typos in "Functional Programming"
typo fixed

might find more...
Merge pull request #603 from gr650/patch-1

typo fixed
typo?

(or not), it sounds better like this, I think. Forgive the nit-picking.
typo

The sentence should be: "Its metaprogramming capabilities [...] allow to write [...] and provide_ [...]"
Merge pull request #605 from gr650/patch-3

typo
Merge pull request #604 from gr650/patch-2

typo?
Missing negation.
Merge pull request #606 from kasterma/patch-2

Missing negation.
Fix "Evaluating..." PDF link
Merge pull request #607 from Welliton309/patch-1

Fix "Evaluating..." PDF link
Update Functionals.rmd

Typo
Merge pull request #608 from michaelmikebuckley/patch-1

Update Functionals.rmd
Book now available
Add ids to index