inject CSS only on sites where it should be injected
add handling of std::vector<std::string> by Communication::{Input,Output}Buffer
add support of frame hierarchy for IsWhitelistedUrl
refactor code from case Communication::PROC_IS_WHITELISTED_URL: into function IsWhitelisted
add support of frame hierarchy for IsElemhideWhitelistedOnDomain
check whether the frame is whitellisted before injecting CSS