Make libstratosphere a submodule

Delete libstratosphere in prep for submodule

pm: Use non-system event for process tracking.

libstratosphere: add ReadOnlySystemEvent helper

libstratosphere: Add thread primitive, WaitableManager->RequestStop()

libstratosphere: Implement message queues

libstrat: Use iterators when looping deferred waitables

libstrat: Significantly cleanup waitable manager result handling.

libstrat: fix potential oob deref in WaitableManager (closes #256)

libstrat: improve waitable manager cancelsync semantics

libstrat: update curthreadhandle for libnx 1.5.0

libstratosphere: Use intraprocess event signaling for new waitable management

libstrat: Allow nullptr buffers if 0 size. (closes #255)

fs.mitm: Cache IStorageInterfaces, store meta on SD instead of memory.

fs.mitm: Fix romfs detection on SD

fs.mitm: Only create storage interface when needed.

set.mitm: fixup NPDM json.

Merge pull request #215 from npdmfixup/npdmfixup ...

Use new npdm-json format

Merge branch 'master' into npdmfixup

Fix make dist zip to launch set_mitm. (Thanks @bakugo).

libstrat: delete old ipc templating.

Add boost as submodule

libstrat: mark ServiceObjectHolder functions const

atmosphere: improve makefile dependencies

libstrat: remove unused struct in serializer

libstrat: automatically detect+format rawdata structs correctly.

fs.mitm: increase thread count back to 5.

loader: update for libstratosphere refactor

atmosphere: add set.mitm to make dist target

set.mitm: Split out from fs.mitm