replace 'user' with 'pw'
Merge pull request #157 from severyanov/bugs

replace 'user' with 'pw'
this+object prototypes: minor code tweak
this+object prototypes: adding @nberardi Foreword
tweaks to ch1, starting to cover 'void' operator
types+grammar: more work on ch1
types+grammar: more ch1 work
types+grammar: lots more ch1 stuff
types+grammar: splitting out ch1 into two chapters, updating, more work on natives topic, started coercion
this+object prototypes: adding final cover art
core: updating status of this+object prototypes title
types+grammar: more discussion of native prototypes, closes #116
types+grammar: added 'value vs reference' explanation, closes #156
types+grammar: oops, code bug fixed
types+grammar: big reorg of content/chapters, more info on undefined/undeclared
types+grammar: clarifying references, closes #160
types+grammar: minor wording tweak
core: adding LICENCE.txt file with CC3-BY-NC-ND licence text, closes #161
types+grammar: minor tweak
typo fixes