Recipes for converting between numbers and strings
Wrote number to string recipe
Rearranged num -> string examples
Added recipes for json.parse() and json.stringify.
Wrote 3 recipes for handling URIs
Merge branch 'master' into numbers
Merge branch 'master' into json
Tweaks
Merge branch 'master' into numbers
Added coverage for toRadixString().
Merge branch 'master' into json

Conflicts:
	book.asciidoc
Merge branch 'master' into json
Fixed broken asciidoc
Merge branch 'uri' of https://github.com/dart-lang/cookbook into uri
Fixed typo.
Removed asciidoc header
Removed asciidoc header
Merge branch 'master' into json
Removed asciidoc header
Tweaks