Modernize C++ usage (#144) ...

* Stratosphere: Use modern C++ idioms in some places

* algorithms like std::for_each are used instead of raw loops

* Stratosphere: Replace more raw loops with algorithms

* Stratosphere: Add a utility predicate function to test for equality with a reference element

This can be used to rewrite some common raw loops using algorithms instead

* fs.mitm: Use variant

* fs.mitm: Use enum class

* fs.mitm: Turn RomFSSourceInfo::Cleanup into a destructor

This obsoletes the need for a custom deleter in other places

* fs.mitm: Use enum class some more

* fs.mitm: Use unique_ptr

* fs.mitm: Simplify initialization

* Stratosphere: Simplify initialization

* fs.mitm: Use unique_ptr (fix memory leak along the way)

The previous code was using "delete" rather than "delete[]"

* fs.mitm: Use vector::emplace_back rather than push_back

emplace_back constructs elements in-place, hence avoiding a redundant element copy.

* Stratosphere: Replace more raw loops with algorithms

* Stratosphere: Use unique_ptr

* fs.mitm: Replace more raw loops with algorithms

* Stratosphere: Prefer move-construction over copy-construction when moving sink parameters around

fs.mitm: WIP LayeredFS impl (NOTE: UNUSABLE ATM) ...

Also greatly refactors libstratosphere, and does a lot of other things.
There is a lot of code in this one.

libstratosphere/fs.mitm: Push WIP support for Domains. Not yet fully working.

fs.mitm: Add HANS-style redirection for System Data Archives.

fs.mitm: Fix sm^H^Hfshax

fs.mitm: Get Title ID on fsp-srv init, Add worker to handle subinterfaces.

fs.mitm: Remove debugging test, fix postprocessing.

fs.mitm: Add hook for postprocessing mitm messages.

fs.mitm: Fix pointer buffer size passed to mitm'd commands

fs.mitm: Implement basic passthrough framework for input commands.