Fix typo.
v6.0.3
fix typo
Merge pull request #83 from mapycz/fix-typo

fix typo
rewrite transform docs
Merge pull request #86 from mapnik/clarify-scale-factor

rewrite transform docs
extent -> extend typo
Merge pull request #88 from incanus/patch-1

extent -> extend typo
Merge branch 'master' of github.com:mapnik/mapnik-reference into dots
update dots reference