Fixed how we evaluate JSON

Using lib json now. All strings are interpreted as unicode right away.
All output needs to be encoded. Exported files are now in UTF-8.
Turtle encoding should work.
Fixed use of xsd: namespace
Fixed accidental reuse of same variable name
Remove overly frequent property type reports
Added further known property types
Fixed detection of correct datatype and globe
Minor syntax beautification
Improved language mappings

Added a number of comments for problematic/unclear cases.
Clarified situation for "no"
+TODO comment for language mappings
+ documentation for some more languages
Private subtags for non-languages like "simple"
Fixed language code for Tokipona
+some comments, typo fix
Don't escape ' in Turtle (allowed bur not neeeded)
Further improved language codes

This largely follows the suggestions of Purodha (P.Blissenbach),
and the content of http://meta.wikimedia.org/wiki/Special_language_codes
Use underscores instead of spaces in sitelinks