[doc/step-2] Spellcheck and grammar tweaks

Spellcheck and grammar tweaks. Also replaced “out of the box”
expression since it did not quite fit.
Merge pull request #46 from chalin/patch-doc-chap2-spelling-and-grammar-tweaks

[doc/step-2] Spellcheck and grammar tweaks
Copyedit the first page.
Merge pull request #47 from kwalrath/patch-1

Copyedit the first page.