Lots of fixes due to grammar/naming changes.
Documentation for core stuff.
Syntax changes.

--HG--
extra : amend_source : 865db376b5e73c1fbab2e14dfd4b91899451877e
Renames module to Main.

--HG--
rename : examples/hello-world/HelloWorld.purr => examples/hello-world/Main.purr
Fixes routing library.