Kernel:Add missing permissions in shared memory & svc
armemu: Join QADD16 and QSUB16 together.

The only difference between these ops is one adds and one subtracts. Everything is literally the same.
armemu: Fix lower-bound signed saturation clamping for QADD16/QSUB16.
armemu: Fix SXTAH
armemu: Fix SXTAB
armemu: Fix UXTAB/UXTAH
armemu: Implement REVSH
armemu: Fix PKHTB
armemu: Fix SADD16

The lo and hi parts of the result were being constructed as a result of hi and lo halfword intermixing from the rm and rn regs. However the lo part of the result should be constructed only from the lo halfwords of rm and rn, and the hi part of the result should only be constructed from the hi halfwords of rm and rn.
armemu: Implement UMAAL
Merge pull request #287 from lioncash/qaddsub16

armemu: Join QADD16/QSUB16 and fix saturation clamping.
Merge pull request #293 from lioncash/sops

armemu: Fix SADD16
armemu: Fix SSUB16

Broken from the same reason SADD16 was.

The lo part of the result should only be constructed from the lo halfwords of rm and rn.
The hi part of the result should only be constructed from the hi halfwords of rm and rn.
armemu: Unset GE flags for UADD8 if results are < 0x100

Reference manual states these must be set to zero if this case is true.
Filesystem/Archives: Implemented the SaveData archive

The savedata for each game is stored in /savedata/<ProgramID> for NCCH files. ELF files and 3DSX files use the folder 0 because they have no ID information

Got rid of the code duplication in File and Directory

Files that deal with the host machine's file system now live in DiskFile, similarly for directories and DiskDirectory and archives with DiskArchive.

FS_U: Use the correct error code when a file wasn't found
Merge pull request #288 from Subv/savedata_stuff

FS_U: Implemented the SaveData archive
Merge pull request #185 from purpasmart96/mem_perm

Kernel: Add missing permissions
Merge pull request #297 from lioncash/ssub16

armemu: Fix SSUB16
Merge pull request #292 from lioncash/backports

Backport more skyeye fixes from 3dmoo
armemu: Combine SSUB16, SADD16, SASX, and SSAX.