Qt cleanups 2

This fixes a build issue on gcc 6 due to -Werror and a warning caused
by boost::optional, see:
https://github.com/MerryMage/dynarmic/issues/83

Qt cleanup

Fixes #2556

Added drag and drop feature to the code

core: add missing errors.h in CMakeLists.txt

Qt/GameList: Use suffix() to parse the file extension

Fixes #2567

added http service enum to the log.h file

completeSuffix returns everything after the first period, which means
that a file such as `foo.bar.3ds` would not get recognized.

Re-organize software rasterizer code

file_sys: change RomFS archive to Self NCCH archive

Small VideoCore cleanups

Fixes #2455