[Core] Try properly showing the main window on raiseTab().
[Util] NetworkDiskCacheGC stubs.
[Util] RAII-based NetworkDiskCacheGC::RegisterDirectory().

Thus made UnregisterDirectory() private.
[Util] Support passing cache size getter to NetworkDiskCacheGC.

Keep the list of all getters.
[Util] Added ComparingBy() to prelude.
[Util] Added Apply to prelude.
[Util] C++11 versions of Apply and ComparingBy.

gcc sucks :(
[Util] That should be #ifdef, not #if.