JSON tests: Wrap Declaration::isDeprecated
Navigation: Properly highlight deprecated decls

Apply strikethrough to the declaration's name in the navigation tooltip.
Navigation: Show deprecated decl names in italic
DUChain: Cleanup files at EOF

Remove kate-modelines where possible. We already have a .kateconfig in
place.
DUChain: Cleanup files at EOF

Only headers, this time.
Minor optimization in DUContext::findContextAt

Saves a few instructions (even in debug builds)