Set visibility for some methods and remove unused ones

* private: checkUnicodeCompliantBrowser(), makesafe(), unmakesafe().
* protected: safeUnicodeInput(), safeUnicodeOutput().
* unused and deleted: safeUnicodeText(), sectionAnchor().

Also updated documentation for touched methods.

Change-Id: I1a46113a6380505aeea71150b6d106ec68423002
Merge "Set visibility for some methods and remove unused ones"