basis.template.html: don't extend Node prototype for contains polyfill
basis.template.declaration: ignore l10n binding when no dictionary could be resolved, move l10n binding processing in applyDefines
basis.template.htmlfgen: fix issue with l10n tokens attribute expression (template function compilation bug)
basis.template.htmlfgen: small fix for unresolved l10n bindings
basis.template: continue work on l10n markup, some improvements

- prohibit node binding on {element}
- don't wrap l10n token content by <span>
- init test suite for l10n in templates
basis.template: make l10n tokens work in build mode