CppTools: Get rid of SearchSymbols::setSeparateScope()

This will make it easier to use a single SearchSymbols instance and a
single run serving all locator filters.

Change-Id: Idb6a3693ad356227d46d0b28fb4c3a5db62b4ac4
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
Add common interface for text formats inside syntax highlighter

Change-Id: I87f64446161a57aea0896f68e4eafacef791969b
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>